lied to by rep to lock me into a contract i never agreed to

I went into T-Mobile ONLY because I heard they paid out AT&T customers to switch over. I was promised multiple different things. One including a rebate of however much I owed on my old phone ($463 and some change. I did everything the lady told me to do. She even told me that she would take care of everything for me!! I call support after going in 3 times with zero help and support tells me that the representative lied to me and I'm just going to have to deal with it until my contract is up. No thank you!! You guys had me sign up for something under false pretenses and that is illegal! Unless T-Mobile would like to hear from my lawyers I'd suggest someone make this right. I should not have to pay $120+ per month when I was promised my bill would be no more than $80. You guys are charging me more than at&t ever was and now AT&T is sending my balance to collections because your company lied to me!!! This is effecting my actual life and credit and it's not right. Do better!