Condo Association Dues

I had an issue with a leak into my unit. Come to find out it was the siding that was causing the leak. My condo assoc. repaired the siding, but while doing so the contractor damaged the shingles on my roof. The assoc. agreed that the contractor was responsible for the damage. The price of the damage was $1400. The owner of the management company said that they are going to hold the money until I repaired the roof. I don't agree with this so I have contacted the management company certified mail tell them that my condo dues will come out of the $1400 owed to me and they refused to pick up the letter after a notice was left by USPS. I sent a second copy with delivery confirmation only. Of course it was delivered since it didn't have to be signed for. Now the association is threating me with a lien on my property. What should I do?