read Texas property code about HOA.
find HOA mistake. Hire an attorney. Write an attorney letter to the board chairman.
I just did and HOA removed my fine that I fight them for about a year.
When HOA add a fine to your account, it must follow certain rules.
I suggest that you spend some time, may be a few hours read the code by yourself.
I think the single family home and condo may have different rules. you can google texas property code for PUD to find related code.
Sorry to type in English.