Deceptive sale practice

I went into Meto Pcs store on 5/18/09 with my old phone which had some water damage, was advised to buy a new phone instead of a new battery. was told I could return phone in 30 day's if not happy with said phone, also the receipt stated all returns in 7 days in original package. when I went back on 5/18/09 to return phone because of poor quality and it did not have features I wanted. I was told I went over my talk time by 1hr and that I had signed a form stating such as well as the sales person went into detail telling me such. I requested said form I allegedly signed, not only could they not produce said form, but I was given conflicting information. they called the sales person who lied and said she told me about contract of talk time and I indeed signed said form. after going back and forth with them, I was told the reason I cannot return the phone was because I kept my old number. turns out my old phone still works, I was lied to and led to buy a new phone which they refused to honor said receipt.