Fined R150 for packing

At Checkout Pinetown, they have tenants in the premises and most of their tenants are hairdressing salons. Clients coming to the salons park at checkout parking lots for saftey (eventhough it is never safe). To my suprise on Saturday i parked my car and went to do my hair. only to find out my car was locked inside because the store was closed. the security guard told me to pay R150 in order to get them to open the gate for me. i was shocked. i did not park my car and leave it, i was in their premises, they have proof on camera as well. i would understand if i was fined for leaving my car in their premises then go somewhere, but i was in the premises, doing my hair in their tenants. i am not happy with this and would like to happy money back. the security guard had no clue who was in charge of this whole thing .