Product: Credit card or prepaid card

I found multiple fraudulent credit card charges and notified the CC ( Citibank ) about the issue. Got issued a new card and thought everything was fine. Then I receive a letter saying that the {$800.00} would not be credited because, being a chip card, I would have had to have possession of it. I did not lose the cards, I did not let anyone borrow the cards nor authorize anyone to use the cards. I still have BOTH cards in my possession. 
Just did a simple XXXX search : New research by XXXX XXXX XXXX XXXX XXXX detailed a method of bypassing EMV technology to monetize supposedly secure cards. This method, EMV-Bypass Cloning, leverages information from one technology ( EMV chips ) and converts it into another less-secure technology ( magstripe ), which allows fraudsters to rely on their familiar cloning techniques. 
To test this theory, they chose 11 cards from 10 banks from US, XXXX, and XXXX issuer countries. The researchers harvested data from four of the cards, created cloned magstripe cards with this data, and successfully placed transactions. 
XXXX XXXX indicates that this technique is already in use among the cybercriminal underground, as seen in the respective breaches of XXXX XXXX XXXX XXXX XXXX and XXXX XXXX XXXX exposing over XXXX compromised cards. EMV technology may have changed the underground market for CP records, but EMV-Bypass Cloning has opened the door for cybercriminals to sidestep the central security features of EMV chips and channel a new source of CP cards back into the underground CP market. 
EMV-Bypass Cloning is dangerously effective, but through policy review and higher verification standards, card providers and financial institutions can close the security gaps that this method exploits and restore the security integrity of EMV chips. 

Chip credit cards can be hacked, in a sense. ... That means criminals can't use it any merchant that has a chip reader. EMV chip cards enabled with contactless technology could also be at risk of NFC skimming.XX/XX/XXXX Can Chip Credit Cards Be Hacked? - XXXX Many of the charges are from places I never shop, XXXX XXXX, XXXX XXXX as well as multiple gasoline fill-up on the same day from the same town. Also has me filling up with gas multiple times a day. This is the THIRD time in 2 years this has happened. The CC card company said the chip is unbreakable and that I had to have had made the charges. I DID NOT AND AM NOT GOING TO PAY FOR SOMETHING I DID NOT DO!!! If they made the card then someone other one can make it to. I have been a customer with this company since XXXX ( 16 years X XXXX x 12=XXXX dollars of business and this is how they treat me ) and have never missed a payment nor carried a balance. I use it for heavy for my business and I usually charge about XXXX a month. 
The more I think about it the more angry I get. 
To add insult to injury, the many of the charges were from XX/XX/XXXX on and could not have been me since my entire family was at home XXXX  from XXXX. I have talked to my bank and issued a block on any further auto pays. At this point I have decided they are a corrupt company and both me and my wife ( separate accounts ) are going to stop using this card.