Product: Debt collection

On XX/XX/XXXX I submitted a complaint with the CFPB regarding an attempt by XXXX XXXX to collect an invalid debt, which they reported on my credit report. Although my complaint was resolved on XX/XX/XXXX and the collection account was removed from my credit report and recalled on XX/XX/XXXX, XXXX XXXX apparently re-sold the inaccurate, invalid, unverified, and unsubstantiated debt to Enhanced Recovery Company ( ERC ). ERC began reporting this debt as a collection account in the amount of {$600.00} on my credit report on XX/XX/XXXX. XXXX XXXX had no right to sell the debt to ERC because the debt is not valid, they were not able to validate or substantiate the debt, and they admitted such when they responded to my complaint against them. I am again disputing this debt, with ERC. ERC is also reporting two different addresses as theirs on my credit reports. 
The following is my original explanation regarding why the debt is invalid : On XX/XX/XXXX I cancelled my account with XXXX XXXX. On XX/XX/XXXX I received an email from XXXX regarding my remaining balance {$1400.00} (  see attached ). On XX/XX/XXXX I communicated with XXXX via their online chat system ( see attached ) and asked if I would be allowed to return the phones, and was told I could return the phones to a XXXX store for credit. On XX/XX/XXXX I returned 3 phones to the XXXX store and I called XXXX as directed to verify the return was credited ; I was told only 2 phones showed as returned in their system. I provided XXXX with the receipt number for verification and was told they would have to do an investigation into the credit for the 3rd phone. I was also informed that I would still be responsible for paying the {$1400.00} because I terminated my contract early. I informed them I would be able to make a partial payment of {$1000.00} as soon as I received the prepaid refund card from my new wireless provider, which could take up to 60 days to receive. I was told as long as monthly payments were made my account would remain in good standing and would not be sent to a collection agency. On XX/XX/XXXX I paid {$400.00} to XXXX via their online system. On XX/XX/XXXX I paid XXXX {$1000.00} via telephone and was told my remaining account balance of {$38.00} for the 3rd phone would remain in XXXX collection dept until refund was credited to account for the 3rd phone. I was assured the account would not be sent to a collection agency. On XX/XX/XXXX I called to check the status of the investigation and was told I only owed for the wireless charging pad that I had financed for a total of {$57.00}. I paid the {$57.00} during that call for the charging pad and I was told that payment satisfied the remaining balance on my account. In total I paid {$1500.00}, which was {$19.00} more than the total amount I was told I originally owed. I did not receive any further bills/notices from XXXX after the final payment I made on XX/XX/XXXX. I also did not receive any notice from the collection agency XXXX XXXX until XX/XX/XXXX, which is months after it was reported on my credit report in XX/XX/XXXX and the dates on my credit reports are also discrepant. The amount being reported on my credit report is {$600.00} with XXXX with an assigned date of XX/XX/XXXX and a delinquent date of XX/XX/XXXX ; {$600.00} with XXXX with an assigned date of XX/XX/XXXX and delinquent date of XX/XX/XXXX ; and {$600.00} with XXXX with a placed for collection date of XX/XX/XXXX. My account was never delinquent with XXXX and they continued to accept payments from me after XX/XX/XXXX, which is the delinquency date being reported on my XXXX  report. I do not owe the {$600.00} or any other amount to XXXX or XXXX XXXX because my debt to XXXX was paid in full on XX/XX/XXXX. I disputed the collection/debt on all 3 of my credit reports in XX/XX/XXXX and XXXX XXXX refused to remove the collection/debt from any of my reports.