Getting out of paying the cost of the attorney's letter

My board had their attorney send me a letter stating my son and his dogs were on the property with no leash. They claimed they had a video. I asked to see it and they sent one with the two dogs tethered together coming out the stairwell door. However, it didn't show my son coming out. He has a leash that goes out ten feet. I asked to see him coming out the door on the video. I'm sure it would have seen him with the leash. The cost of the letter from the attorney was $625 and they want me to pay for it. According to our house rules, an owner would get a letter from the board in regards to breaking a house rule. After that, there are to be 3 more warnings with a fine with each warning. Then, if not complied, with a letter from the attorney. So that are four steps before a letter from the attorney. In our case, the board went right to step five. How do I get out of paying the cost of the letter, when the board didn't give me the proper notification?