You can expect a payday loan company to do whatever it can to collect the money, including trying to have you prosecuted. Don't do anything which could cause you to face a bad check charge.

If you do close your checking account, make sure you notify them in advance (in writing) that you are revoking the authorization for them to make withdrawals from the account, and that the account will be closed as of a specified date.

While stopping the payments won't stop them from trying to collect the debt, or assessing additional fees and charges as described in your contract, you neet to take care that it can only be pursued as a civil matter, not as a criminal matter.