Debi check mandate

FNB I have been endlessly trying to reverse a debit order from January 2025, which was a mandate, the company refuses help, don't answer messages. FNB says sorry it's a Debi check mandate we can't do anything. It's a amount of R2700 and I know Debi check mandate can't be reversed but should I just loose this amount of money because no one wants to walk the extra mile. What happened to FNB, how can we help you? I don't know anymore what to do.