Debt collector has failure to pay posted to my credit report?

I sent debt validation letter and they sent back a partial copy of a credit card statement with my name and a totally different address and city. 9 months later they had a Law firm send me a letter telling me to pay this or else. I disputed it with them and they have not sent anything back and stopped contacting me. I then disputed this with the credit bureau and they say I need contact the debt collector via phone. I have in the past sent debt validation letters to this collection agency asking for a signature to verify that this debt is mine as the address is NOT. If I am correct the status if limitations is up in Aug this year. But because I disputed this through the credit report it will stay now till June of 2012. What should I do? I have asked for validation several times and now they posted Failure to pay and that an agreement was made with them and I never went into an agreement as this is not my address and they have not shown proof to my knowledge that it is my debt. Please advise and thank you :)