$700 over payment... now past due?

Question

ten year customer.... i made my $70 payment, but fat-fingered the amount, and actually paid $770.  so my account showed a $700 credit.  fabulous!  so the following month when the statement printed, they deducted my following month's charge of $70, and i had an account balance of $630; a credit owed to me.  i get my statement and think "$630 credit.  i'll call them and get that refunded"
ya know, i could totally pay the rent with that, so i called and said, hey maybe cut me a check for the remaining $630.  sure they said, we'll send that $630 check right out! 
then, less than 5 days later, i get the calls from collections saying my account is two months past due and i need to pay another $160 NOW or they will cancel my service.
so i call in and find out they haven't sent me a check for the balance ($630), but they HAVE reversed the entire payment instead.... they think.  the phone reps at version really can't tell me what form of payment the refund was made or where it was sent.  they don't know if a check was mailed.... they can't tell if an electronic payment was made.  they don't know how and they don't know the amount. 
what they DO know is that they will cancel my account in 7 days if i don't pay them another $160 immediately.
my bank says it will take 8-10 days to credit back IF they receive it due to the large amount of the refund. 
my question:  when a person makes a $700 overpayment to their account, what is the correct question to ask to get the balance refunded WITHOUT throwing one's account into collections?  if the representative would have said "hey, i see you made an overpayment, if we refund you, we'll turn you over to collections , we'll cancel your account before you have money to pay your bill and you'll have to shop for another account with sprint" i wold have at least been prepared to shop around.
what really should have happened?  i can't pay (my new) balance because the money hasn't been sent to my electronic account yet.  verizon wants to cancel my account because they say i'm past due since they refunded too much money, they say.
after being with verizon for a decade,  i can't imagine shopping for another plan, but i'm looking at less than a week before i need to port my number.  how can i resolve this situation?
and i still don't have my $700 back...... and i'm the bad guy.
what to do?

Answer 1

No, the poster noticed it on the next billing cycle and not at once.
Based on the $700 overpayment Verizon took the $70 out for that next month.
When they asked for the overpayment of $630 Verizon in their error refunded $700 which then threw them in arrears for $70.
Additionally Verizon now jerked them around not to refund the credit balance. But instead demanded payment for an error on their part via refunding too much back.
This is not the original posters problem. However 9 days later no refund back to her bank because Verizon is once again shining the customer on. It does not take 10 days to electronically place money back into an account that was charged instantly. It is just a reversal of overpayment.
Could the customer contact their bank and had it reversed instantly more than likely. That is what I would have done. My Amex credits me in seconds this way no messing around pulling teeth to get your over payment from Verizon.
For right now I would simply call the bank for a reversal credit, pay the balance owed to Verizon and be more careful in the future.
Good Luck