I'd definitely sue.
If you know he has $, then he' can't escape a garnishment.
You can likely get the money back that you put into it. Maybe you can add some late payment fees as well.
(Always include the late fees in your contract that you make customers sign. $10 per month, etc, for bills with a remaining balance at the end of the month.)
You can also recover court fees on his dime. This includes the cost of paying someone to go serve him, and the money it took to file the paperwork.
If he is subpoenaed, he must pay between $60-80 usually, depending on your state, to even answer and attend the hearing in small claims court. If he shows up, you present your evidence, and you win, usually he forfeits these fees, and more, to you.
If the guy doesn't show up, you will probably win by default, and get an automatic judgment against him, for whatever amount.
When you have a judgment, you can get his bank account garnished. Depending on which state you live in, and what the local laws are, you can suck the money right out of his bank account before he is even notified. For example, as of right now, no notification of pending garnishment is needed in Oregon.
If his bank balance is low, you may not recover the entire sum. However, you get the extra pleasure of knowing that you probably caused his outstanding checks and debit transactions to bounce, resulting in a few hundred dollars in bank fees for the guy.
