Product: Debt collection

*the dates mentioned below are recalled to the best of my knowledge. 
This debt arose from a rental lease on a townhome in XXXX XXXX condominiums, the property was managed by XXXX XXXX in XXXX, FL. I was on a previous lease for the same address from XXXX XXXX to XXXX XXXX : this lease included myself ; my husband ; and our roommate. During this lease all rental payments were made as required per the agreement. After the XXXX lease ended, my husband and I moved out and a vacate agreement was completed. 
The remaining tenant chose to stay in the townhome and signed a lease by himself as the tenant for XXXX XXXX XXXX. In XXXX of XXXX, this tenant spoke to XXXX XXXX and advised them he would be breaking the lease and vacating the townhome. XXXX XXXX lead him to believe as long as another tenant moved in he would not owe further payments, unfortunately this was not in writing. The tenant then vacated and relocated to another home. In XXXX of XXXX, XXXX XXXX sent this tenant a letter regarding the remaining rental payments that he is responsible for per the lease agreement, totaling {$6100.00}. This letter incorrectly has myself and my husband listed in addition to the tenant. XXXX XXXX never reached out to my husband or me ( or we could have cleared this up back then by showing we were not on the lease in question ). The letter also does not indicate the dates of the delinquencies, but per my credit report this did not post until XXXX XXXX. 
I was never contacted regarding the debt, nor was my husband. We only found out from the remaining tenant that our names were listed on the letter but we never saw it on our credit report. A few years ago Ideal Collections informed the remaining tenant on a phone call that I was also responsible for the debt and that their collection was on my credit report. After receiving this false information I tried to reach out to Ideal Collections and the company never responded. Since we never saw the account on our report through XXXX XXXX we had nothing to dispute except what the collection agency, incorrectly and without our permission, shared with the other tenant. 
My husband and I are currently going through the process to obtain a mortgage. The first time my credit report was pulled this account from Ideal Collections did not appear. When they re-pulled credit, the Ideal Collections account then appeared showing past due for {$6100.00}. My mortgage company asked for clarification of this debt including dates delinquent etc. I took action and called Ideal Collections and asked for verification of the debt. I was sent only XXXX pages of the prior lease with all three of our names on it and the notice that XXXX received in XXXX of XXXX. I then contacted XXXX realty and they advised the records were in storage. I then sent XXXX XXXX the records I have showing both leases and the vacate agreement but have not heard back. I have since notified Ideal Collections that the lease they have on file is for the incorrect dates and asked them to validate the delinquency dates and also to acknowledge that neither my husband nor I are financially responsible for the debt. A representative advised that she would reach out to XXXX XXXX and request the delinquent dates. I have also contacted XXXX in an attempt to dispute the debt which shows oddly on my credit report but not my husband 's. 
This problem appears to stem from XXXX XXXX not providing Ideal Collections with the delinquent dates and correct lease agreement, instead they sent an incorrect lease which was paid in full and had nothing to do with the payments they were owed. I am attempting to resolve this dispute and also report both XXXX XXXX and Ideal Collections for not verifying the debt before pursuing collection actions and posting the false account on my credit report.