Mark purchased a very expensive automobile on credit. Within a week, Mark discovered that a tune-up was necessary, for he was in the habit of driving at an excessive rate of speed. When the car was repaired, the bill was more than $1,000. Mark does not have the money to pay for the car repairs or the monthly car payments. The credit company as well as the repair shop are concerned over who has priority of repayment. Who has priority and why?