Why would you loan someone $2,000.00 if they could write a check for that amount? Was it post-dated?
You've got a civil option and a criminal option. You could just sue your ex in small claims court for the $2,000.00
Or, you could contact the local law enforcement agency (police or sheriff, depending on where you were when you made the loan) and report it as a theft by deception. R.C. 2913.02. Because the amount involved is more than $500, but less than $5,000.00, it would be a fifth-degree felony theft offense.
It could also constitute as fifth-degre felony passing bad checks. R.C. 2913.11. But they won't charge him with both.
I'd call your ex and tell him to pay up or else you'll have to report him.