We bought a house at an auction. The previous owner owes $400 in HOA fee and a collection agency sent us demand letters asking for $2000. We don't think the $1500 collection fee was reasonable so we called HOA. The 1st time I called, they said we don't owe anything. 2nd time I called they said they don't know how much we owe but we can pay them directly and they'll let us know if there's a balance. So we sent them a check of $400 (including late fees) and it was cashed by them last week and today we received another letter from the collection agency titled "Notice of Delinquent Assessment Lien" and the lien is in the amount of $2400. Could they have filed a lien without going to court with us? Can they file the lien after cashing our check? What can we do if we disagree with the amount?