Select Choice Unlimited FAM TT 50

So, it came to my attention that T-Mobile decided to raise our rates by $5 per line plus taxes. The price lock agreement we received when signing up for this plan stated that our rates would not increase. I asked T-Mobile to send me a copy of our signed contract, and they refused to do so. What part of this is legal, and for those of you that are on the same plan, how are you planning to deal with this unexpected increase? We've been a customer since 1999, and then we switched to our current plan around 2005-6. T-Mobile now claims the signed service contract is for the device ONLY, and they don't have service contracts anymore. Well, newsflash, when we signed up for the "Select Choice Unlimited FAM TT 50" it was a 2-year contract, and we liked it so much, we ended up staying with this plan all these years. Are there any attorneys that can chime in on this? This seems like a deceptive business practice to me.