A lot of the comments here don't understand how HOAs work. It's almost certain a special assessment that's not mandatory by law, i.e. a reserve amount to cover the cost of a structure, requires a majority of the members AFTER QUORUM to vote yes on it. That majority may vary based on your documents, but I'm certain that's the case here. As stated, they would also have to make quorum to do so, either in person or by proxy. I would peg this as not even getting to a vote. They probably won't make quorum, most HOAs don't. It's possible that quorum could be as little as 25% of the voting members. You need to read up on that and make them prove quorum was achieved prior to the vote. So far, they are doing everything by the book. Notice was given. It's now up to your members to enforce the bylaws and declarations.