Unauthorised debit order amounts

On 26/11 I received a price increase letter from Discovery insure . On 27/11 I contacted them directly and asked that they relook at the price. After review the price was dropped and an updated letter sent to me on 27/11. On 27/12 they deducted R8.77 more than the amount on the plan schedule. As it was a small amount I ignored it. On 28/01 they deducted a slightly higher amount than the plan schedule sent on 27/11. When I contacted them they advised that the annual increase in Jan was app****. I was quite upset because when spoke to the agent on 27/11 he did not advise of further increases. Further more even if there was an increase Discovery failed to communicate this to me. I have asked on several occassions that they send proof of having advised me of the Jan increase and they keep referring to the 26/11 communication. I have explained several times that the plan sent on 26/11 is null and void as it was replaced on 27/11 with an updated schedule. My issue is that Discovery has seen fit to increase my policy premium without consulting me and this is unacceptable. They have no right to deduct a different amount from my account without my consent. I also am not happy to accept the increase because I specifically called and had this amended. I want somebody at Discovery to send me the email where it was communicated to me that my premium increased to the current amount being deducted. When I ask for this I am sent an email with a higher amount. I have also on email asked what my cancellation period is as well as the process to have their tracking device removed but I am still waiting for a response on this.