1) call the Card issuer (normally a bank)
2) ask if you are legally obligated to the money outstanding on the card
3) if yes, ask your employer to remove you from the card
4) if no, ask the card issuer why it's being reported to the credit bureaus and require them to STOP doing that.
5) ask your employer and the bank if that is a 'business' credit card or a 'personal' credit card. "business" credit cards are not supposed to be reported to personal credit reporting agencies in any event.