You have a difficult situation.
Leaving the vehicle there for a month without checking on it and without letting Pep Boys know what was going on is mostly likely damning in your case.
However, the argument you could put forward is based on the law of bailment.
A bailment is "the relation created through the transfer of the possession
of goods or chattels, by a person called the bailor to a person called the bailee, without a transfer of ownership
, for the accomplishment of a certain purpose, whereupon the goods or chattels are to be dealt with according to the instructions of the bailor". Dobie on Bailment & Carriers as quoted in Refining Co. v. Harvester Co., 173 Md. 404, 414 (1938). . . .
"To constitute a bailment there must be an existing subject-matter, a contract
with reference to it which involves possession of it by the bailee, delivery, actual or constructive, and acceptance, actual or constructive." Refining Co. at 415.
Once the bailment relationship is proven certain responsibilities flow from the relationship. The bailee in accepting possession of the bailed property assumes the duty of exercising reasonable care in protecting it. Hambleton v. McGee, 19 Md. 43 (1862).
So, the argument would go that because Pep Boys accepted the vehicle, they were responsible for exercising reasonable car in protecting it. They failed to exercise that reasonable care by not contacting you to ask you to remove it and having it towed instead. The tow and storage charges are your damages.
This will be a very difficult argument to win in a court. They may respond back that when you leave a vehicle at a garage, if you do not pay them, they have a right to charge you storage fees. This argument is supported by state law as well.
I suggest you contact Pep Boys and make this argument with them. Tell them that they were negligent by not contacting you before having the car towed and thus are partially responsible for the charges. Tell them if they do not help you out, then you will be forced to sue.
If they do not cave, you are going to have to bite the bullet and pay the charges to get the car out. Then you will have to sue them for the rest.
Regardless, if you do not remove the car from the tow yard, the towing company will have a legal right to foreclose a lien on the car and become its legal owners in order to satisfy the charges. In other words, the towing company gets paid no matter what.
Please let me know if you have any further questions. Please also kindly consider rating my answer positively so that I am compensated by the website for my work on your question. Rating positively does not cause an additional charge and does not prevent us from further discussing your questions.