There's no "debtor's prison" for anything CRIMINAL here, but there's still a CIVIL claim for your breach of the contract to pay as you agreed. You probably didn't promise to pay "ASAP," and they didn't agree to be your bank and lend you money, so you'd be in breach and they can sue you for that.
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Short answer: No you cannot be arrested for breach of contract.
It seems that you have a contract for the repairs, and you made partial payment on the contract (10%) and you agreed to pay the balance (but the time ASAP is not a definite date to pay the balance).
In Florida, a mechanic can file a lien on your vehicle, for unpaid repairs.
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No, it's not a crime to fail to pay a debt. As answered by the previous attorney, however, he can sue you in court. I am surprised he let you have the car without full payment. Mechanics have a legal right to retain a vehicle brought in for repair and can impound your car until paid, or file to have title transferred to them if you do not pay.