I've had things go to collections twice in my life, both times were some bill I forgot about and moved away and the first time I heard about being delinquent was the collections call. One time I asked for the evidence and they actually did mail me all the documentation and proof of the debt. The other time I asked for documentation and ended up never hearing from them again. I still don't really know what that debt was, it never appeared on my credit history or anything else.