Towing Issues: towed last night, tow company, towing company

Question
Last night I was helping a friend clean his condo before he deployed to Iraq. Two hours later I came out and the car was gone and had been towed.  Apparently I missed a sign at the entrance that says permit parking only, but I did not notice it when I came in.  Further, none of the spots had any signs or warnings.  THis was a new policy - guests had previously been able to park there before.  We contacted the towing company just after they left with the car and they refused to return it.  Instead, they took it to their lot and demanded $430.  We eventually persuaded them to come down to $180 and got the car back, but I want to know if it's legal for the HOA to have a car towed based on only 1 sign at the entrance.  Don't they have to warn you first?  Also, was it legal for the tow company to take the car back to the lot once I called them?

Answer
If you live in California all the answers to your questions are on my blog, sftow.blogspot.com

If not in California I cannot answer the question.

The sign must be at the entrance to the lot as you say it was. It must also meet certain other criteria all explained in my blog for California residents. No warning is required except for the signs. The driver is not obligated to return your car when you call him. You must retrieve from the storage lot. He could have done so if he wanted to, but he didn't. Probably because he would make more money by towing it in and storing it.