increase in billing contract broken

I have been contracted with T mobile for many years. I just spoke with a customer care person who stated that T mobile never had contracts for the service. I stated multiple times we did have to sign a contract and we were locked into that contract. she basically told me she had been a customer for 15 years and never signed a contract for the service. This attitude infuriated me. She kept saying that a text went out in May, well that text looked like Spam and I didn't open it. what is T mobile going to do about our contract they signed saying we were being locked into the rate with up to 4 voice lines? Do we need to call the FCC? The contract was presented and signed by both parties and is legally binding by both parties.