Unfairly treated

What a terrible experience iv had with northmead square security for clamping my car. Had knocked off already to do my shopping at the square and because of the weather condition I decided to park where apparently I'm not supposed to park . when I came back from the shops found my car clamped, had to pay R200 which I never signed up for nor given terms and Conditions of their policy. All four of my colleagues parked with me their cars were not clamped which I really find very strange and unfair on me. On top of that the terrible attitude I got from the security guard together with the centre manager i m really disappointed and upset