Walmart Family T Mobile I was having problems with a phone I purchased at one of the local Walmart stores, After about two months I was having problems with it. California

I took it to the store and they sent me to TMobile I then called customer service and was told to take it to TMobile representative at the Best Buy store. Still not able to use my phone I called Family TMobile again and told to take the phone back to Walmart. I was told there that they couldn't exchange the phone because I had no box. By then I am totally frustrated, so I called customer service again and explain to them i wanted the service cancelled therefore I don't believe I owe you anything. I have a phone I purchased for about $80;00 that's no us to me and you are trying to charge me for service I did not use