How come Yahoo never answers back when you contact them with any kind of questions that are not on their FAQ?

I asked Yahoo a question over a year ago and many times afterward as to why when I 1st signed up for my yahoo account,(mail etc) after about a month I tried to get into my account and they keep telling me that my user name or pword was invalid and I even have a copy off the paperwork from the day I signed up that proves them completely wrong?( I printed it out so I would remember it all in case I forgot) Since then I had to make a whole new account and still have never gotten and answer back from them and now the name I signed up with can never be used again by anyone and I tried to tell them that of course it is because I signed up with it but to this day I stiil can't get into it or an answer back from them!!!! It really meesed me up in alot of ways because my main address name is different now somewhat from my yahoo one because of this!