Product: Debt collection

XXXX XXXX, 2015, I received a call from Optimum Outcomes, Inc. stating their attempting to collect a debt in the amount {$1000.00} dollars for XXXX XXXX. I told the caller that I was not aware of any bills owed and to send the bills and statements so I can look into them for verification. I was told that this would be placed in dispute status and the information I requested will be sent out. 
On XXXX XXXX, I received a letter dated XXXX XXXX, however, the post mark for mailing was XXXX XXXX, 2015, 8 days after the letter was drafted. Please see the attached copies. In this letter, XXXX additional debts in additions to the one I was called about and a balance of {$3100.00} is now being called due. Again, please see the attached copies. 
I called Optimum Outcomes, Inc. again on the XXXX in question of the additional listed debt. I explained to them that XXXX has multiple clinics and hospitals and that I needed copies of the original bills, the names of the Doctor 's offices and what branch of XXXX XXXX these pertained to. I was told that I would have to send my request to them in writing for that information. I also pointed out that XXXX of the additional debts listed were over 10 years old and that North Carolina has a 3 year statute of limitations on debt collection. Again I was told that I owed these debts and any further request for information would have to be made in writing. 
I also reviewed my credit report and found that Optimum Outcomes, Inc. had also recently placed derogatory credit in the amount {$1600.00} in my credit report damaging my credit score. 
On XXXX XXXX, 2015 I drafted a very detailed letter, please see attached, again asking for more information and to point out the XXXX time dated debts Optimum Outcomes, Inc. was attempting to collect on. This was sent by certified mail, received and signed for by XXXX XXXX XXXX XXXX, 2015. On XXXX XXXX, in response, I received XXXX individual letters in separate envelopes, XXXX pertaining to the time dated debts and XXXX pertaining XXXX in the amount {$1000.00} but nothing on the {$1600.00} that has been placed on my credit report. Please see the attached. The letters basically state that the debts are valid because the time period ( 30 days from first contact ) for my response had past. 
I called Optimum Outcomes, Inc. back and was told that I was out of time. When I explained that I disputed this on the first call received and that I have been in correspondence, I was told that the 30 days starts from first contact which was by phone and my letter was received beyond that 30 days. I again questioned the time dated debt and was told all debt is valid and they needed payment. 
In addition to these, every time I called, I spoke with a different person and each had no knowledge of any conversation with any other representative. With each person I spoke with, I specifically asked for a first and last name as well as any employee I.D . for record. All refused to provide a last name and claimed they do n't have an employee identification system. The different ones I spoke to all stated that I 'm the only XXXX, XXXX, ETC that works here, just ask for me when you call back. When I have called back and asked for a specific person, I 'm asked for a last name and am told we have many people working here by that first name and with out the last name, they would n't know who I spoke with. 
I have been trying to work this out for 3 months now and have gotten nothing but the run around from Optimum Outcomes, Inc. They are only interested in collecting money and have not provided a shred of the information I requested nor do I feel they have complied with Fair Debt Collection Practices and are in direct violation of North Carolina law by pursing time dated debt.