Need VZW to deal with this, very uphappy customer

Question

I’m submitting this complaint, hoping Verizon Wireless management can help me out in a situation in which I feel Verizon Wireless mislead/deceived me.
My wife and I have been Verizon Wireless customers for approximately 7-8 years, we always pay our bill on time and have been great customers.  We have always just got 2 year contracts with basic flip phones and avoided smart phones due to our frugal nature.  I didn’t see having a phone with data package as a necessity.
My wife’s phone had been acting up, periodically turning itself off.  We dealt with it for a few months, but decided it was time to get new phones.  Our previous 2 year contract had ran out a year or so ago, so we were eligible for a phone upgrade.  We saw an upgrade deal from VZW for free iPhone 4s phones.  Using the Verizon Wireless website to shop around, the price to upgrade to the new model of the basic phone we had would be $50 a phone. So we weighed the options and plans and looked into the iPhone 4s.
After running through the plan options numerous times, we decided to keep our same voice plan, have no text plan and share a 2GB data plan between two new iPhone 4s phones. On the last page of the “Customer Agreement checkout” (of which I have a screen capture), our “cart summary” states that our monthly cost will be $79.98, which is right around the same price as we are paying for our basic phone plan.  I said to my wife, this seems too good to be true, but it states right here “$79.98 – Monthly”.
Using that as our justification to purchase the phones, we agreed to a new 2 year contract on March 2, 2014.  We received the phones via FedEx on March 6, 2014 and received our monthly bill on approximately March 12, 2014 for $204.45.  I’d been expecting our bill to be around $160-$170, due to the fact that the cost of our phone “upgrade fee” was $60 and included in the next months bill, so was surprised to see it for $204.45.
I didn’t have time to contact VZW until this afternoon on March 22, 2014.  I spoke to two VZW reps, one a customer service employee, the second a Supervisor named Athena.  I explained to Athena and emailed her a copy of the checkout cart summary which stated our monthly bill would be $79.98.  She said that that didn’t take into account the voice plan we previously had with our basic phones which we continued to use for our new contract with the iPhones.
I told Athena that was very misleading; nowhere in the checkout process did it make clear that the cost of the voice plan wasn’t taken into account in the checkout cart summary.  We would not have upgraded to the smart phones which now cost us approximately $120/mo, vs. the approximately $80/mo we paid with our basic phones.  The $40 cost of the voice plan should be included on the “checkout cart summary” giving us a “true monthly cost”.  Athena told me that she didn’t know why the cost was not on the checkout cart summary and that she did not design the website.
I told Athena I’d like to return the iPhones, which would remove the data plan costs.  I’d also like to purchase new basic phones (the current model of our old basic phones) which would keep our monthly bill at approximately $80.  She told me that we were at day 16 of the VZW 14 day return guarantee.  This means that we cannot return the iPhones, we own them and are locked into a new two year contract.
I told Athena that we received the phones on March 6, but didn’t have the bill until approximately March 12, which means we haven’t even had 14 days since receiving the new monthly bill for approximately $120/mo.  She said this didn’t matter, the 14 days started when we received the iPhones, not when we received our bill.  I asked her to bend a little and extend us a 2 day grace period so we could return the iPhones.  She would not. 
I said this is very misleading and deceiving, based on the “Customer Agreement checkout cart summary” we should be paying $79.98/mo. 
Athena offered to find us a cheaper plan for our smart phones, but couldn’t get us back down around to the $80 price range we previously had.  Her only idea was for us to sell the iPhones on our own (since we now own them, it’s been 16 days vs. 14 ), find/purchase some old basic phones, then call VZW back and “Change Devices” from iPhones back to basic phones.  This would remove the data plan and get our monthly cost back to around $80/mo.  I said that sounds like a pain and that we would be back to square one, except that we were now locked into a 2 year contract, based on what I felt was a misleading checkout system and a tardiness of 2 days.
I told her that I was very dissatisfied and said that they would lose my wife and I as customers as soon as our new 2 year contract was up.  It seemed as Athena didn’t care.  The way I look at it, I’m locked into a 2 year contract based on misleading information and can’t do anything about it.
So that’s my situation. Feel that VZW took advantage of my wife and I because we “Should have known” (Athena’s words) that the cost of our old contract’s voice plan would be added onto our new contract.  On top of the $79.98/mo cost the checkout cart stated.
Nowhere in the final “Customer Agreement checkout cart summary” was the "True Monthly Cost"stated.  If it was, I never would have upgrade our basic phones to smart phones. 
I’d love to be able to send my iPhones back to VZW and go back to having 2 new basic phones (the new model of our old contract’s basic phone model) under a 2 year contract.  VZW would still have me locked down with a contract, I'd have the cost point I expected to have.
Thanks,
Matt

Answer 1

What you have done there only ensures that one thread can execute that particular update at a time. You should do this regardless, since you wouldn't want two threads both getting into that code -- you might get prod_qty from one thread and prod_no from another thread.
However what you have done there doesn't prevent two customers from both ordering your last widget. And I don't think locking the table will help. What you need is a method that does this:
- Get the product record
- see if there is anything on hand
- if there isn't then set on the out-of-stock flag (or whatever)
- if there is then decrement the on-hand quantity and update the product record
And this entire method needs to be synchronized on some object.