

What a frustrating situation. Being without a vehicle for any length of time, especially 47 days, is incredibly disruptive, particularly when it affects your ability to work. It appears that one of your questions is whether you can recover monetary damages for the body shop exceeding its scope of possession of your vehicle, or keeping your vehicle longer than it estimated it would. The answer to that is: Maybe.
Generally, you cannot recover mental anguish or lost wages, akin to pain and suffering, unless there is a tort component - a civil wrong or injury, other than a breach of contract. What you have is a contract dispute. Damages can vary significantly, and without knowing more, I cannot say whether hiring an attorney would be economically sensible for you. However, small claims court might be an option.
Small claims courts are designed to handle disputes involving relatively small amounts of money, and claims for damages due to delays in repair services fall within their jurisdiction. In cases such as" Dixon v. X-Treme Body & Fender Inc., 20 Misc. 3d 130(A)," courts have recognized that a delay in returning a vehicle can establish a presumption of negligence against the repair shop, shifting the burden to the shop to prove it was not negligent. This principle is based on the creation of a bailment when a vehicle is delivered to a repair shop, and the shop's failure to return the vehicle on time can lead to liability for damages, such as the cost of renting a substitute vehicle during the delay. Dixon v. X-Treme Body & Fender Inc., 20 Misc. 3d 130(A), Burane v. Poppy's Auto Wreckers, 13 Misc. 3d 139(A).
Now, I'll address the other situation about possible overpayment. It sounds like you paid this body shop based on the invoices you received when you picked up his car. If I were you, I would be interested in knowing what basis the body shop has, other than an email, that you owe them an additional $2,400. Based on the information you've provided in your question, the body shop should adhere to the contract, evidenced by the signed invoices and payments they accepted when they returned the vehicle to you.
I recommend asking the body shop to provide evidence of a contract that allows them to charge you more than the amount stated in their invoices. Additionally, I recommend speaking with an attorney who is experienced in contract disputes.