John Gill Commentary Philemon 1:18

"But if he hath wronged the at all, or oweth [thee] aught, put that to mine account;" — Philemon 1:18 (ASV)

If he has wronged you
By squandering away his time, spoiling his work, or corrupting his fellow servants:

or owes you anything ;
by embezzling his master's goods, robbing him of his money, and running away from his service:

put that on mine account ;
Signifying that he would be answerable for all, and make good all debts and damages.