I am not positive that it has been "sold" to the collection agency. I was only told they hold the account now. Are these one in the same?
Doesn't really matter.
If the account was sold then the collection agency controls and collects.
If the account was assigned to the collection agency on a commission basis, then there is a contract between the HOA and the collection agency saying that the collection agency controls and collects and the HOA doesn't.
You could try negotiating a lump sum cash settelment to reduce some of the fees, but the collection agency has no obligation to accept anything other than 100% of the arrears plus interest, fees, and costs. Your contract with the HOA makes you responsible for all of those additional costs.
You are especially vulnerable because the HOA can just put a lien on your property while the balance grows to double or triple the amount over the next few years if you keep arguing about it.
Bottom line: You screwed up by going into default. Your only way out is to pay what the collection agency says to pay and move on. They have you over a barrel.