Need Hoa Advice

I received a letter in the mail from a lawyer stating they were a debt collector and will proceed with lien / foreclosure process. I know I got behind about 2 months.( HOA is only 400 a year) But during the time I got behind they started nitpicking me over some bushes in my yard. I didn't realize that each time they sent a letter it was 35$ plus a late fee so in the short course of time I racked up a debt of 747 and some change. I responded the the lawyer to pay this debt and they sent me and email saying I know owe 987, And any further communication will result in more legal fees. My question is how did I go from 747 to 987 ?! They locked my portal for my HOA payment and have to go through them. Did one phone call speaking to just their secretary really cost me 200?! Do I just pay or try to show them the original letter? I'm beside myself as this is a huge unexpected bill that has me ready to sell my house over this. Please help.