I can understand your frustration. If I were you I would begin by filing a complaint with your State Attorney General, then send a dispute to all 3 credit bureaus disputing the account. Include proof of your current address and a copy of your social security card if you want the results of the investigations mailed to you. Include copies of your compliants, a copy of the cashed check and any other supporting documents. The credit bureaus have 30 days from the date they receive the dispute to verify or delete the item. Here is a copy of a free credit repair kit
http://www.expert-credit-advice.com/fre ... repair.htm which has everything you need to do it on your own. If the dispute does not do the trick, you may want to consider send a validation demand, then following up with another dispute to each credit bureau. If they are harassing you, send a cease and desist order.