Is it legal for HOA to charge $100 per day for violations?

We live in a HOA community and no commercial vehicles are allowed in driveway per our bylaws. There are six commercial vehicles that have been parked in homeowner driveway since we moved in 2007. Which makes it obvious no action was taken. Also we have a couple homeowners that have a car lot in their driveway (they sell vehicles and they are not tagged or insured). Another homeowner is on the HOA Board and he parks his commercial vehicle in his driveway. He told my husband he park his vehicle at his residence is seasonal. Nowhere in the bylaws does it state you can park seasonal. Another homeowner never moved his vehicle, he moved out of community. We own a commercial trailer and received a letter for a hearing for us to move our trailer. We were out of town the day of the hearing. I called and spoke to property management and told her we were out of town and we would like to reschedule. She sent me a email stating that the hearing committee made a decision and I would receive letter in the mail. I received letter and they gave me 5 days to remove trailer. We did not move trailer because we are on waiting list for storage. Now we are being fined $100 per day.