Product: Debt collection

In XX/XX/XXXX I went to XXXX where I purchased an all in one XXXX XXXX and a wireless speaker from them. Although I had cash on me, the individual at the store back then told me it would be preferable to open an account with them as I would benefit from the the interest for six months deal they got going on. I took the deal. 
Then the same year I got an XXXX mini and XXXX Wireless speaker for my wife then girlfriend as a birthday gift. 
Then later on I think in XX/XX/XXXX, I purchased a wired in-ear XXXX headphones for {$99.00}. Ever since then, I stopped making purchases from XXXX and focused on paying the account that was opened through XXXX XXXX. 
When I got married in XX/XX/XXXX, I opened another account with XXXX XXXX with XXXX XXXX XXXX. I was then paying these 2 accounts together. 
In XX/XX/XXXX I fell ill and could no longer work, after a while, hospital bills drained my savings and I found myself calling my creditors so they could freeze my accounts until I could get back on my feet. XXXX XXXX  flat out told me that it wasn't possible. I asked them to get me a summary of what I actually owe them so I could have my parents assist me, to my surprise, they gave me a bill for XXXX that I should not be having at this point considering the length of time I spent without touching the account, I told them that I should be done paying it if not paid off already. 
I asked why I still owe that much, they listed my purchases for me and told me of recent purchases that SHOULD NOT be on my account, I made it crystal clear to them that I have not made any other purchase since XX/XX/XXXX and that anything beyond that point should be considered fraudulent. 
When the lady asked me for my XXXX card, that is when I realized I didn't have it in my wallet or anywhere else. 
So we concluded the call that my misplaced card was obliviously used to make unauthorized purchases, that without those purchases I am in fact done paying the XXXX account, the lady told me that they would take care of it but there was nothing they could do for the XXXX XXXX XXXX account, they could not freeze it. 
I had to let that account get charged off just like some other creditors who told me they could not freeze my accounts either. 
I got a new job in XX/XX/XXXX and started contacting my original creditors to find out that most of them had sold my account to Debt Collections agencies I have been paying them since them and almost have very little left before i am done paying them and naturally, the XXXX XXXX XXXX account is one of them that I am still paying for. 
In XX/XX/XXXX, a number started blowing up my phone from 9 in the morning until I got off at 5.

When I got off and picked up their last call, it was PORTFOLIO RECOVERY, telling me that my account was sold to them from XXXX and I owed {$780.00}. At first I was confused because I was already paying the account they sold, but then the lady explained that it was for XXXX.

I SPENT OVER 1 HOUR IN THE PHONE EXPLAINING TO HER THAT I NO LONGER OWE ANYTHING TO XXXX. 
That is when she apologized and told me that she would put it in for dispute and even congratulated me when I told her that I need them to make sure it's taken care off because I am trying to fix my credit to buy a house since my wife and I are expecting our XXXX  child by the end of XX/XX/XXXX.

I checked my credit around the XX/XX/XXXXt to see how much increase I had gotten. 
There, was PORTFOLIO RECOVERY for {$780.00} for the fist time showing as an unpaid collection. 
I called them in the same week to express my frustration at the fact that they're messing up the credit that I am working so hard to fix, the girl I spoke to told me that i would have to file a police report or wait 10 to 15 days for them to send me a package in the mail that would allow me to dispute the charges even though she acknowledge that it is already in dispute!!!!