Poor Communication Skills

I am a new customer, upon the first call my debit order was arranged for R129 monthly. Then I received a debi-check from them through my bank of which I authorized the debit order, but then a month later I received another debi-check mandate, I phoned them and they assured me that it wasn't them that sent it. A couple of months went by and I noticed that my monthly premium was changed without authorization. Upon phoning them they stated that their monthly premium had changed and they had sent me an email informing me, I was not informed of this so I reversed the debit order until this matter can be resolved. When you do happen to phone their call center you wait and wait for long periods of time for them to eventually answer just to have someone on the other end that doesn't have a cooking clue of what the time of day is never-mind the status of your account, all that they can say is "pay". So the question is: Who authorized you to change my debit order without my knowledge?