My question involves towing laws for the State of: Indiana.

I was parked at a shopping plaza, walked across the street to get something, came back and bought something else at the shopping plaza I parked in and as I was walking out of the building the tow truck was pulling up. There was an employee of the towing co. parked in the lot watching me as I walked to a different shopping center right next to the one I was parked in. When I saw this guy standing next to my car waiving the truck over I ran outside and he said, give me a 100 cash and we'll drop your car. I said I didn't carry that kind of money on me and away the truck went. I was towed because I left the premises but I bought something in the center I was parked in. Are they able to take my car with me next to it? There weren't any signs were I parked but I noticed them scattered around the parking lot later. Also, there wasn't anything to indicate what the "premises" were. There wasn't a shopping center list or sign to say which stores were in this plaza's parking lot. I have the receipt from the store I parked by and even talked to the manager. They don't own the parking lot or the building; the company rents from a person who owns the buildings and lot. Am I able to get my refund from the corporation or do I have a case for small claims?