Product: Debt collection

I first wrote Portfolio Recovery Associates, LLC, requesting this account they claim to be mine be fully validated on XX/XX/2019 for a second time, after I received my free annual credit report. My reason for requesting those reports in the first place was to establish whether I could be qualified for a line of credit to have a much needed medical procedure done. Portfolio responded to my validation request with a letter dated XX/XX/2019, and informed me that their proof of validation was two attached papers. What was included was a letter from an XXXX XXXX informing someone with a name similar to mine but different address that a debt had been sold to Portfolio and a bill for some type of line of credit from the same company addressed to another person with a similar name ( it is different than the first letter ) but a completely different address than the first letter and myself. 
It is my understanding that this is not information to validate this account actually belongs to me and not someone with the same name ; therefore, I sent a response on XX/XX/2019, advising Portfolio Recovery Associates, LLC, that they had failed to properly validate that this account indeed belonged to me. I gave them specific requirements needed to validate this debt and that they lawfully could collect on this debt, per my rights. Also, to make their investigation easier, I included a form to fill out with the exact specifications that are needed in order to validate this debt is in fact accurate, belongs to me, and that they have the legal bonding and lawful requirements to collect on this debt. In writing, I allotted them XXXX days to obtain complete details for the form to validate the debt. 
They sent a response, dated XX/XX/2019, advising they were attaching more documents that would provide validity of the account. It was the exact same two pages they sent prior with their response dated XX/XX/2019. My form was not in there and they had sent me the EXACT same generic response they had done before. At the exact same time, they sent an additional response that was dated XX/XX/2019. This once gave a little bit information, but it was not my form, their bonding information, license, or anything I requested. It simply stated that at the time of sale 3 years ago, they were given an electronic file to include a name, last 4 digits of a social security number, and the date an account was opened. Again, they included the EXACT same letter that XXXX XXXX sent to someone with a similar name but different address than myself. I had nothing showing where I actually signed up for this account, nothing proving they could collect on this debt, nothing telling me the last time a payment was made, where all the charges for an over {$600.00} debt was coming from. 
I assumed that the responses received in XXXX ( dated in XXXX though ) had to be the results of some type of human error on disregarding the letter and just hitting a button for generic responses. This prompted me to give them another chance to validate this debt. I responded on XX/XX/2019, advising this was my 4th attempt at trying to have Portfolio Recovery Associates validate this account. It again advised them of what specifically I expected to receive and by law had the rights to request, and yet another form to fill out in order to make validation easy for whichever one of their representatives handled my letter. This time they were advised that I know they had already been allotted more time than the law mandates and I expected a response within 15 days of them receiving my FOURTH request or they would need to stop pursuing me for this debt immediately. 
Today, I finally received a response back from Portfolio Recovery and it is them advising me that they had not received any additional information pertaining to the account. They blatantly disregarded and ignored multiple attempts to legally validate this account actually belonged to me. I am being restricted from getting a much needed XXXX because this is reporting on my credit report and causing problems for me to be approved for the additional funding needed. I've done a lot of research with this since there has been months of this going on back and forth, so I'm able to know when my rights have been violated.