Toyota Financial Services payment delays

This is really annoying. Since I had a contract with TFS 2019 it was never easy for me, each time they record payments late like 6 to 8 days later and blame the other bank where the money is coming from. Now I've paid them the last payment and they still charge me interest on that, I've asked to be called back and get clarity of why is that and there's no response. My credit score is affected and they do not care. I've been complaining since 2019 and I hope this is the last time and do not want affiliate with them anymore.