Product: Credit card or prepaid card

My Capital One credit card was used for fraudulent activity, so I called to let them know. They cancelled the card, and offered to send me a new one. At the time, I was in XXXX XXXX, so I asked that they send the card via courier ( XXXX, XXXX, etc. ). I was told that they don't normally do this, but then after asking their manager, I was told that it would be sent via courier ( I believe they said XXXX ). 

I didn't receive the card, but noticed a charge for {$1400.00} from " XXXX XXXX '' in XXXX ( as written on my statement ). I called Capital One right away to say that I had never received the card, but that the card number ending in XXXX, which I had never received, had made this purchase. Over the phone, they said they would reverse the charges. 

Then, they investigated the fraud, and sent me a letter dated XX/XX/2019 stating that there was no evidence of fraud. They said that because the card has a chip, and it was actually used to make the purchase, there was no evidence of actual fraud. The letter also said that my card wasn't reported as lost or stolen, but I actually DID report that I had NEVER RECEIVED the card when I claimed that I had not made the purchase ( I think this clearly counts as lost/stolen. ) The letter said that they needed to hear from me within 14 days ; however, I was out of the country at the time, and the letter was sent to my home address. By the time I received it, it was past the 14 days allotted to dispute the investigation. 

When I called the number listed, I was transferred over and over to the collections department. They said the case is closed and there is nothing they can do. 

I asked how the card was shipped, and it was shipped to XXXX XXXX via USPS, even though I specifically asked for it to be sent via courier. The postal system in XXXX XXXX is unreliable at best, and can be quite insecure. It is clear to me that someone in XXXX XXXX, possibly working for the XXXX postal system, opened the envelope with my credit card, and simply used the card to make a large purchase. ( I have since received another replacement card which was sent via XXXX, and that card arrived ready to use with no activation required. ) I would like to know if Capital One has a copy of the signature used to make that purchase. They told me that I would need to get in touch with the merchant to look at the receipt. I have no idea who the merchant is, because I did not make the purchase! The only information I have is what is listed on the statement ( XXXX XXXX in XXXX ), but I do not know anything more than that. I have googled it and have not figured it out. Furthermore, I believe this signature, if available, would be on file with Capital One. The customer service representative said that all they can tell me about the merchant is what is written on the statement. 

Capital One refuses to engage with me about this purchase and continues to say the case is closed, and that I am responsible for that charge. I am 100 % sure I did not make this purchase because I never received the card with the last four numbers XXXX, and I do not recognise the purchase at all. 

Meanwhile, my account is accruing late fees and interest, because I have not paid for the purchase that I am disputing. 

I have closed my account with Capital One out of frustration, despite banking with them for at least 10 years. 

Many Thanks in advance for your help.