I dont think they have any legal right to clamp you at all ! but I am not sure.
The problem is that your development have asked them to come in and clamp cars ! I think the only company that has a right to clamp you is the government clampers.
I know people that have taken the clamps off and just left. They got no phone calls, no court summons, they did not even get asked to pay for the damage done to the clamp. If these private clampers were really legal, I would assume that they would have brought the person to court for damage and non payment of release fee.
Why dont all of you just tell them you dont want their service anymore !
I thought most of the parking spaces with Apartment blocks are leased to you on a yearly basis ?