Unfair practice

So i just received my statement for a loan i took last year in October and i noticed an "arrears amount" which was odd since i never missed a payment so i called your call centre and spoke to an agent that told me that you people track payments before the actual authorised date for debiting and when you don't find any money you penalize your clients and charge them "arrears interest" when you are the once that went against the date that was signed on the contract. I get paid on the 25th, you decide to "track" money on the 23rd/24th and you charge me extra as if i'm in bridge of contract??? how is this fair?? this is actually ********.