This is a gray area as it would have been much better if you had a letter or something other than a text. If the neighborhood has these types of fences, I would let them make the first move. As to can they lien, file lawsuits, etc.- is answered in your restrictive covenants and the bylaws of the HOA. In general most HOA's are operated by people with little or no experience. As an attorney we often find they fine homeowners but have no authority. I would contact an attorney who handles HOA's and get their opinion. Good luck.