It depends on whether that was part of the "agreement" between you and your company *prior* to them attempting to charge you. Employers and employees can agree to essentially any payment arrangment or scheme they chose, including ones with charge-backs and penalites, but there must be agreement before some punitive aspect of the payment or commission plan is invoked. So if you knew that your company could do this (and knowing it, still chose to work for them, thus implicitily showing your consent or agreement), then they most likely could; however, it was never explained to you that this was a possibility, your company should not have the right to do this.