There is no general legal obligation to send a certified letter or other notice first. If there was a requirement that they do this in the HOA agreement or similar documentation, then they would be contractually obligated to do so--they have to follow the rules setting up the HOA. But in the absence of such a documentary requirment, they can go directly to filing a lien.They can also add those other charges if the HOA documentation permits it, since in being a unit or homeowner, you, too, are bound by the rules in those documents.So checking the documents establishing the HOA and governing it is the first thing you should do now.