Most credit cards require you to notify them "in writing" of any dispute for charges. Call them and ask what procedure you need to follow. The only dispute we ever had was with an office where the "owner" would not let anyone else make any adjustments including applying your electric deposit to final electric bill and then refunding the remainer( but you could pay if you owed more). As we were there checking out we placed a call to the owner and demanded our credit be refunded before we left. Finally got it, but would never go back there again.