Prepaid data keeps quitting despite not being close to limit

[unsatisfiedcustomer10]

I am hoping someone here is smarter than the verizon customer service.   We have had a prepaid (allset $45) plan since october.  They messed up originally on our charging and renewed a couple weeks early.  Now every month or 2 we lose data about the time that first plan would have expired but the rest of the phone keeps working. We take it in to the local "corporate office" and they mess around with it for an hour, spend 1-2 hours on the phone with support and getting it going occasionally.  They have had to swap out the sim card twice and that has not helped. It is always something they do on the phone customer service that gets it running for 2-3 weeks and then the data quits working again. Anyone smarter than the verizon customer service and know what is going on and how to fix this? (I am using a galaxy S4 that I bought through verizon if that helps - but I don't think the phone is the issue.)