Clap your car for no reason

I parked at Pick'n Pay in Douglasdale planning to go say hello to a mate across the road buy some groceries and go home.<br> <br> The security guard warned that if I wasn't a customer of Pick'n Pay I would have my car clamped. I said fine fully intending to buy groceries after popping in and saying hello to my mate.<br> <br> Came back 10-15 mins later and my car was clamped decided stuff this I won't shop here anymore bought a sandwich because I was hungry and came back.<br> <br> They are refusing to unclamp my car even though I'm a customer which is what there sign states.