For 2 and a half years every month they up the charge of my bill

For 2 and a half years every month they up the charge of my bill. I have been charged additions to my plan, causing bill increase. On March 22 or 23 I spoke with Austin who after reviewing my plan & payments she assured me my bill would now be $58. for going forward. Two days later T-Mobile took $69. out of my checking account. Now new bill came in at $79. I didn't add anything to my plan. Yesterday I spoke with someone at T-Mobile about cell plans. I told her Mint mobile offers plans at $15. per person. So she gave me $10. off for next 6 months. So my bill should be $48. for 6 months then $58. after that. The t mobile is known for Cramming & slamming, adding dollars each month to ur bill for no reason. All agents seem to lie consistently. I am elderly this is a crime to take advantage or scam the elderly in MA. If my bill isn't fixed I am forced to complain to Better Business Bureau & FCC as well as file a small claims case. All conversation r recorded aren't they, I did record my conversations with T-Mobile. Also on the internet in a paragraph for 55 and over plan, u can get for $30 for 2. Then u try to change it & charge $30. Per person. Please fix my bill & don't take more than $58. out of my checking account on the 25th of April.