Can't receive SMS messages from Verizon Iphone 6 user

Question

I have had an iphone 6+ since it came out.  I've had my imessages turned off for several months because it was eating up so much data (all of a sudden...never an issue with my 4s before my upgrade.).  Just in the last day, I've noticed I have not been able to receive message from my husband, who also has an iphone 6+ wtih Verizon.  I've never had an issue with receiving his messages before yesterday when they just stopped.  It shows on his phone that it was sent via SMS on his phone, but nothing shows on mine.  I called other family members with iphones and Verizon as well and they have said they have sent me messages as well with no response from me, but I never received them.  What's the deal?
1. All are iphone users
2. All are on Verizon's network
3. Sporatic timing of non-retreival of messages
4. iMessages work, but I do not want to use them as it has already caused me to up my data plan twice since upgrading to a new phone.
5. I've restarted my phone several times with no improvement

Answer 1

Hi Yosef,
I had to delete every one of my apps that I transferred over from my 4s and I was still going over data.  I used all the same apps from my 4s and in the same manner and frequency. (I tracked my data useage for 2 years and i never went over 2gb of data).   I turned cell data off on EVERYTHING except for facebook which I check occationally and google maps.  Once I turned imessages off, I wasn't getting overages.  (but I had to increase my plan twice to insure that).  Now I can't use the apps I used to have and can't use them except on wifi without going over my data allowance within a few days of my plan starting each month.
I've messaged some family members and they indicated that their messages to me were automatically changing to imessage, though i have had it shut off since October.  I did restart my phone yesterday, but changed no settings, which is when I suddenly couldn't recieve messages anymore.  All the previous threads were in SMS.  Why would it change to imessage within an SMS thread just from a phone restart?