Unfortunately, you may little recourse fighting your HOA. You have to understand how much power they have over you. To them, you're just a peon, a nobody. Those certified letters were notices to you informing you of missed payments.
Taking an HOA to court is nasty business, mostly for you. Most likely you'll lose and end up with all their legal fees. Lovely, huh? Yes, I agree, a phone call would've been nice.
So it's best just to pay what you owe right now, instead of delaying it or ignoring. Don't bother taking them to court.
It's best to deliver payment in person, and insist on getting a receipt for proof of payment.