Product: Debt collection

I sent a letter to Regional Acceptance CO. on XX/XX/XXXX via certified return receipt mail, which was signed for on XX/XX/XXXX. I requested validation of the referenced account, bearing my signature. The same day they signed for my letter they shot out a response to my letter, no attachments, nothing with my signature. After 30 days I checked my credit report. It had not been marked as in dispute and now is in violation of the FCRA. Additionally, my credit report is being marked as key derogatory every month which causes my credit score to go down and they are indicating that a charge-off account has a past due. This is incorrect reporting. A charged off account does not a balance as it was charged off and written off as bad debt, allowing the company to take a tax break. 
On XX/XX/XXXX I receive a letter from a company called XXXX offering a settlement on the account. The account that they refused to validate. 
I wrote another letter to Regional on XX/XX/XXXX. I told them I wanted this account validated, bearing my signature and requested the name address and telephone number who verified this alleged debt without proof. They signed for the letter on XX/XX/XXXX and prepared a response to me on XX/XX/XXXX. The letter looks to be nearly identical to the first letter, with only wording from XXXX sentence rearranged. My credit report is still being marked as key derogatory every month, continues to show as a charge off yet a past due balance. Attached is a copy of my credit report dated XX/XX/XXXX Between XX/XX/XXXX and XX/XX/XXXX Regional Acceptance was removed from my credit report. 
I again sent another letter on XX/XX/XXXX. I told them they failed to provide me with any evidence, I felt they were acting in bad faith and that they had 15 days or I would be seeking legal resources. This letter was signed for on XX/XX/XXXX and on XX/XX/XXXX, they wrote me a letter back again the letter looks to be nearly identical to the first letter, with only wording from XXXX sentence rearranged. Still, my credit report is being marked as key derogatory every month which causes my credit score to go down and they are indicating that a charge-off account has a past due. This is incorrect reporting. A charged off account does not a balance as it was charged off and written off as bad debt, allowing the company to take a tax break. 
Attached you will find a copy of my credit report dated XX/XX/XXXX and low and behold Regional Acceptance has been added back on to my credit report. I was never informed that this account was being added back on to my credit report - This is a credit reporting violation. Also you will see that it has now been 90 + days since my initial dispute with Regional Acceptance and my credit reports have not been marked as in dispute. To this point, I have never been provided anything with my signature as request on XXXX separate occasions over XXXX separate months and my credit reports were not marked as in dispute within the first 30 days, as required by law. 
XX/XX/XXXX XXXX sends me a settlement offer of {$1700.00} XX/XX/XXXX XXXX sends me a settlement offer of {$1900.00} XX/XX/XXXX I get a letter from a collection agency named XXXX indicating the balance as XXXX. Now this is contrary to the amount that is both listed on my credit report as well as the amount they are indicating in their letters and on my credit report as past due. I am provided with a print off of a computer screen. The Balance listed on the printed sheet as of XX/XX/XXXX is {$15000.00} however another letter they included indicates that Regional indicated that the amount due to them as of XX/XX/XXXX ( 7 days earlier than the previous date ) is {$17000.00}. They claim the vehicle was auctioned for {$9600.00} however never produced a bill of sale or proof of sale to val