Yeah that happened to me once when I was 20. I bought a $3,500 TV set at a now bankrupt electronics store (The Good Guys it was called) I never made a payment and they never came after me (it was one of those 12 months no interest no payment until the next year deals) . A year or so later I declared bankruptcy and thought I better send a bankruptcy letter to them too. So I mailed the letter and it got returned to me. When I tried to locate them, I kept getting the same address to send the letter to. Sent it again and again it came back as undeliverable or something like that. I ignored it and just decided...well I'll just put them in the bankruptcy and they wont know about it...if they come after me later, I will just show them the returned letter to say I tried to contact them.
They never tried to contact me and never messed with my credit report. As far as they know, I never declared bankruptcy (since they never got the BK letter)
On another note, Pacific bell had a collection against me and I ended up paying it 3 times because everytime I paid it, I didnt keep my reciept to show them I paid it.
Another one is a debt with college. They sent a letter to a collection agent saying I owed them $600. I didnt. I talked to collections and told them the story about how I dont owe it and they just sold the debt to someone else that put it on my credit report. I had to explain the story again, but they wouldnt take it off my report and refused to let it go. Then I went straight to the credit bureaus, wrote all my letters and got it off my credit report. Now here it is 4 years later and I just got a letter in January and apparently another collection agency has it now. Doesnt bother them...they buy and sell this debt for anywhere from 2 to 10 cents on the dollar and go from collection agency to collection agency. If one agency cant collect debts, they sell it to another one and if that one cant collect they sell it to another one. Sometimes they sell debts that were already paid too. (Which is why I had to pay Pac-bel 3 times) I found this out when I looked into getting into the debt collection business.