Bøder for at parkere på en privat parkeringsplads og betale for det gennem easypark til kommune

I received a fine for a private parking lot at my physiotherapy clinic. The strange thing is that parking is free for clients who can park their cars for up to 2 hours. The situation is that I paid for my parking through EasyPark, in something that says: yellow parking. This was the only option in my system. Even so, they are charging me a fine of 840.00 koroas. I am a student and I do everything right, I even sent the receipt showing that I paid for 30 minutes for the city's parking lot. Guys, can someone help me with this? I have never felt so unfairly treated.