I can certainly understand your frustration, but without knowing who you are and the circumstances regarding your account it is hard to comment. If your payment was not cashed by the Management Company, are you sure it was received? Normally they would just credit the overage to the next year or issue a refund. Also, how long has this been going on? For the fees to reach $3500 this must have been going on for some time.
I can say that the normal process is for the Management Company to send several notices of non-payment and then a letter notifying of the release to the attorney by a specified date. The attorney then makes several (3 to 5) attempts to work things out with the homeowner. The letters are sent certified mail and the request is to contact their office to resolve the situation. They even have a process server hand deliver papers to the homeowner when close to foreclosure.
Please contact the Association Attorney, you should have their information, and make arrangements to settle your account.