You are in fact doing the right thing by making your son pay for his actions. He is of the age to be considered an adult and should be treated as one. He should not expect you to pay for everything especially since he makes money. You are not stealing his money. Who does he expect to pay for the "extra" expenses incurred on his credit card? Soon, he will be paying for nearly all of his expenses. You are simply preparing him for that day which will come sooner than later!!!
If this has helped. Please ACCEPT. Have a great evening!!!