AT&T AT&T Would not stand behind the contract I made with they,now they have me oweing them $593 and I live on SSA with no way to pay that much money Nationwide Nationwide

In May of this year 2017  My contract with Verizon ended and I was looking for something cheaper for phone service.So I called AT&T and the agent on the phone said oh you qualify for this and that,well at the end of the conversationshe told me that if I paid $118 that dayand agreed with the contract it would cost me the $118 today and I would be billed $150 per month locked in for 2 years.So i agreed because it was $10 dollars cheaper than what i was paying at Verizonso i was changed over.The vary next month i got a bill for $593..So i called AT&T and talked to an agent and was told that there was no way that a agent could lock in  a contract like that,so that means that the agent that I talked to to swap over plain outright lied to me to get me to change over to them.all month of june i was on the phone with AT&T supervisors and other loyalty agents and they told me that when i sent back their internet equiptment and it arrived at the warehouse that my bill would roll back to 000 Now they are bikking me $593 and telling me that it is a valid bill for eqiptment charges so i was lied to again by the person that said my bill would roll back to 000 Now i did pay $118 up front and paid $150 exactly what I was stated my bill would be when i changed over that was around May 18th and i canceled the phone service in late June..I swaped over to Streight Talk and when i was at walmart the lady  that i was dealing with told me she used to work for AT&T but had to quit because in her training she was told to lie to customers and tell them what they wanted to hear to get them under a contract.I have talked to about 20 different AT&T agents and every one has told me something different.In other AT&T fraudulenty got me to change over to them, I need help,there is no way a Disabled person like me can pay that kind of money liveing on SSA