You've rolled several questions into one post. Ordinarily, a change to the flip tax requires the approval of a supermajority of shareholders. It's possible, however, that your governing documents give that power to the board. You'd have to check.

Failure to pay your vendors is not "criminal," but it's bad behavior that could lead to legal claims by the vendors. It could also make it harder to engage vendors/contractors in the future.

Almost all co-op by-laws require an annual meeting of shareholders, along with a board election. You may need to engage a lawyer to force a meeting. That would be an expensive proposition on your own; see if you can get other shareholders involved.

Couldn’t the shareholders vote for a “special meeting” and really for an election?

Yes, provided there is the appropriate language in your co-op bylaws. Generally, that's how it's done, but some customized or amended bylaws may contain non-standard language so there is no definite "yes" or "no" answer.

After your review of your by-laws but before you take any unilateral action, I *strongly* advise you (as Carl Tait did) to solicit the support of other shareholders. This group could also form the basis of a slate of opposition board members who run against your current board at the next election.

Good luck!