Car clamp by condo security

It happen when I visit my aunt which is in a condominium.After let all the passenger out my car I go to park my car.When I pass by the parking lots in front of the swimming pool area I saw my other relatives cars that visiting my aunt also parking there. So I park there also because previously there is visitor parking. And there is no sign or label also.After I visit my aunt and want to go back home I saw my car wheel is clamp.My other relatives car nothing.So I ask the guard why clamp my car?He said the owner complaining.Then I ask him to open it and I will go now but he insist me to pay RM50.We have long arguement about this and even my aunt that stay there came to talk with them also they insist me to pay RM50.My aunt said previously there is visitor parking but because of the greedy management they sell to owner.But nobody know whether really owner but it.Anyway I just want to know whether they have right to clamp my car since there is visitor parking before and now they never put a sign or any label that show there is owner parking now?I feel very unfair if they can simply clamp people car and the owner complaining and ask for RM50.