Sounds like a tough situation. Here are some initial thoughts that may help.
Contact your insurance company: You should contact your insurance company as soon as possible to report the theft and file a claim.
Document everything: Make sure to keep a record of all interactions, such as contracts, the police report, any conversations you had with their staff about the theft, etc.
Possible Causes of Action against Maaco:
A claim of negligence applies if Maaco failed to take reasonable care to protect your car. For instance, if they left it unlocked in an unsecured area or did not have reasonable security.
Breach of contract applies if your agreement with Maaco included terms about how they would secure your car, and they failed to uphold those terms. Review the specific contract for this scenario.
Bailment may also apply in this scenario. Bailment is a legal relationship in which one person (the bailor) transfers possession of property to another person (the bailee) for a specific purpose. The bailee has a duty to use reasonable care in taking care of the property. If the bailee fails to use reasonable care and the property is damaged or lost, the bailor may be able to sue the bailee for damages. See here for more information on bailments.
Feel free to contact us at (303) 688-0944 to see if we can help.