If the company previously (prior to you leaving employment) paid (Or reimbursed, if you initially paid) any charges on the card which were charges validly or properly incurred in the course of your employment, for the employer's benefit, and within the confines of any rules or parameters for what you could charge, then they should not now be able to force you to pay those charges. Even in the absence of a written agreement to the effect of the above, if sued, you could use the company's demonstrated course of conduct--i.e. the fact that it did pay these work-related charges--as evidence of an agreement under which it would pay all such charges.Where they might have a valid claim, however, against you for outstanding balances on the card would be if:1) you charged items or services for your own benefit, not the company's; or2) you charged more than you were allowed to charge; or3) you incurred charges after leaving employee.In those events, they could certainly seek reimbursement of those charges.