Rookie Mistake...

Excellent step. Now tell him you did that and you demand the car be finished by April or there will be legal action that may result in the los of his business license.
I put the bug in his ear after I stopped in on 12/14/2023. I texted him an image of the check from my credit union. Dated 4/22/2022. Politely reminding him it's been almost 20 months since he took my car and my money.