Questions about past due assessments, collection fees and liens almost always include a statement the inquirer did not receive notice. Not having your correct mailing address on file with the association puts the liability on you. Just like not signing for the certified letter is on you and the association will receive it back marked “UNCLAIMED.”
If you are going to dispute any charges, here is my advice:
Pay off the lien first and then bring a separate action for recovery of any fees if the association violated your due process rights. Never risk the loss of your property to prove a point or fight over improper fees.
Hire a HOA/condo lawyer to audit the fees and bring any possible action. You need someone who is experienced not only in this area of the law, but the industry practices.