Your "preacher" is a con man and a liar. Sold you a defective car and now threatens to sue cuz you stopped the check? You are very lucky he was willing to take a check in the first place. This guy sounds like a professional troublemaker (they are out there).

You may wish to consult an attorney to protect yourself. Any reputable attorney will meet with you for a single free visit to discuss your situation.

Good luck.