HitBTC Account Drained - Inactivity Fee Dispute

I've held a small amount of Ripple coin on HitBTC since almost 2017. I've accessed my account approximately 6-7 times throughout the years, and on each occasion, my balance stayed consistent. But, the last time I looked at my account, all my money was gone. I sent them an email, and their reply was quite surprising. According to their policy, they deducted $20 per month from inactive accounts since I hadn't logged in for 6 months. According to them, it was for security purposes. They gave a silly reason for the inactivity fee, claiming it covers manual processing costs and ensures secure storage. Why wasn't this policy enforced sooner if it existed? It seems like the system is unfair. Where is the appropriate place to file a complaint? I require the help of an expert. If others are experiencing the same problems, let's unite and submit a joint complaint to the authorities in our countries.