Product: Credit card

I purchased a used computer that was described as 100 % working and never had any issues. The computer I received had defected hardware and the computer was not functioning properly. After researching the problem I ended up finding out that the seller knew of the problem and had information to prove it. I contacted the seller and he continued to lie and say he never had an issue with the computer. Not getting any resolution with the seller I started a dispute with Capital one. The seller fought the chargeback, again saying he never had a problem with the computer and that the issues I was having was due to software I put on the computer. At this point Capital One said I needed a second opinion letter to basically say that there was something wrong with the computer and I was n't making it up. I took the computer to XXXX, the manufacturer, and they ran tests and found defected hardware in the computer. They also ran the serial number of the computer and found XXXX issues reported by the previous owner. XXXX of the issues was the same issue I was having. I called Capital One on XXXX XXXX, 2016 before uploading all my information and documents that was given to me by XXXX. I wanted to confirm that I had everything that was needed for the dispute. I was told at this time that my second opinion letter was good and that there should be no issues winning the dispute with the information I had. I sent my information in and was told I should get and answer in 10 working days. After 18 days and no reply from Capital One so I called in on XXXX XXXX, 2016. They said they could n't find the documents that I uploaded to them. After a supervisor got involved they found the documents. I again asked if all the documents needed were found and that everything looked good. Again I was told yes, I provided everything needed and in two weeks I should have an answer. Two weeks go by and still no word from Capital One so I called again on XXXX XXXX, 2016. This time I was told again that the information was not found and the case has not been looked at by anyone. I got a supervisor to talk to me personally this time and I told him that I uploaded them and he said, OHHHH here they are. He put me on hold to review my information. He came back and said, yes, I can see from this information that you do have a legitimate case here but your second opinion letter was missing something. I explained to him that I was told twice that the letter had all the information need. I asked that since I was never informed of the issue with the letter, what could I do to fix it. He said there was nothing that could be done because of time frames, too much time had past from when I uploaded the information. He said that if the case was reviewed when it should have been in the first two weeks, then they would have told me to get the letter fixed but since it took so long for Capital One to find my information, the time frame when things need to be finish had already past. So even though I proved that the computer I received was defected and not as describe, Capital One closed my dispute in favor of the seller. Capital One acknowledged that I was given wrong information by them and acknowledged that my dispute case was not handle in a timely matter. It is not right that I have to pay for the mistakes made by Capital One.