Credit card or prepaid card — AMERICAN EXPRESS COMPANY (FL)

Card was charged for something you did not purchase with the card. On XX/XX/XXXX my American Express credit card shows a transaction for {$630.00} described as " debit adjustment ''. The CC company is unable to tell me exactly what this is, who the vendor is and I made no such purchase for this amount. I contacted the CC company 3 times -- XXXX XXXX XXXX XXXX. They keep telling me they are looking into it but they don't know how this transaction originated. They have refused to reverse the " adjustment '' even though they don't know what it is.