I own a small business and was brought a job to replace a part on a vehicle. The customer gave a $400 deposit for me to tow his vehicle from his home to my shop. I completed the tow, but he decided to have it towed by another company to have the job completed cheaper at another shop. Our towing policy is, if I fix your vehicle you will not be charged for the tow, and if someone else fixes it you are charged for the tow. I refunded $340 out of $400 because I charged him $60 for the tow (which is usually $80 but I cut him a break). Can I be sued for not refunding his full amount?