Tired of the run around with prices and services! And increases out of nowhere....

Got my latest combined bill. Cell phone portion of bill is over $13 more than last month for two phones on an antiquated grandfathered in plan. Loyalty Dept. couldn't explain why bill has gone up - said that is just the price now but will credit my bill "this time" for the overage because I wasn't notified about the increase but that will be the price moving forward - over $120 for a 12 mb shared plan with 2 phones a month and WITH a $40 monthly discount.  But being we have combined bill and all the services on it are screwed up on different billing dates, I won't even see the credit for it on this bill.  So I am just postponing the inevitable and the credit right now is a joke.  Why did our bill just go up AGAIN?!?!?! Should we just go with TMobile or some other carrier at this point. Was told via chat what we have the cheapest they even offer.