Unfortunately a lot of people consider it good practice not to take credit card payments for credit agreements as it encourages people to juggle their debts rather than paying them off. There is always the option to use a cash advance but, because of the charges (3% fee plus a higher interest rate?), this is unlikely to be a good idea.
I am sure that, if you went into a Honda dealers to spend £20 in their shop, then they would happily accept a credit card payment. Most finance agreements, however, cannot be paid with a credit card.
I tend to drive old cars. I also get angry when my car gets keyed but, with an old car, it isn't the end of the world. Often, if the scratch isn't too deep, you can remove it with either a rubbing compound or a colour-matched polish and some elbow grease. However, after a polish, your car will look smart and shiney and if the kids near you are anything like those here, they will scratch the shiney ones before the grubby ones.