20% increase on my premium???

I want to complain about the ******** & shady nonsense your division is trying to achieve. Discovery Insure started insuring my new Merc from Sept. The premium was in Oct/Nov R3 527.44. I called in to ask for a DQ tracker installation, your consultant told me about a new benefit, which will get my premium reduced. I obviously signed up for that as it made money sense. So premium became Dec R3 364.29. To my horror, this month of January, a debit of R4 058.61 went off my account. I called in & had to deal with an inexperienced consultant who couldn't assist jack and told me that he'll refer the matter to some other Dept for review. He couldn't even tell me what the percentage increase was. I've been your customer for years, and to be subjected to a 20% increase without having to explain is despicable and tasteless. The only explanation was that it's a annual increase which kicks off in Jan. My car is only 4 months old and already there is an increase? You are not the only insurance around, bear in mind I will cancel and I will advise whoever cares to listen on social media to do same. This is absolutely ridiculous. What a freaken rip-off!