Stupid payment system and unhelpful call centre

Called the DirectAxis Call Centre today to request my debit order be increased. 1stly the IVR asks for my ID, then the consultant asks for it again, for what? Then I am told the debit order can not be changed. He suggested I rather make additional payments, when I confirmed that I am already doing that and I asked why the additional payments are not being taken off the capital amount, I am told thats not how it works. What a stupid system, seriously. When I asked to speak to a supervisor, I was put on hold for over 5 minutes.