Midland Credit acquired my Verizon Wireless account

In late March upon discovering a Verizon Wireless account on my credit file I wrote verizon a letter asking who, what, when, where etc. About two weeks letter this account was acquired by midland credit management, who promptly called me about this much to my surprise. I told them not to call me anymore that I had no idea about the debt etc. They asked I send them a police report and when I refused due to lack of information, they threatened legal action. I politely ended the phone call and sent them a letter via certified mail not to call me and asked them for a copy of the signed cellular phone contract. Instead I received another letter offering a settlement which was $50 off the amount owed. I again replied via certified mail asking for a signed contract. In this time Verizon sent me a letter referring me to Midland. On May 24th I received a letter from Midland demanding payment with the statement, "Per your request, enclosed are documents for the above referenced account". Again no signed contract, and what they have provided was a cell phone statement page, which listed an address I had never resided at. I am replying again in Bold face type my request for the signed contract via certified letter. Per the fair debt collection practices act they are to cease collection activity yet this is still on my credit file. Any ideas?