Complaint that was not answered

Good day, my account was debited with R40 extra, according to Vodacom, ot is the insurance, but when I spoke to the, on facbook messenger, tjey told me that their premium is still the same, it did not increase, furthermore I was not informed about the increase. After a while Vodacom pho ed me and they did check, I was then told that I had an discount from my previous contract, that it is expiring the end of January 2020, and that is why the increase, but they keepnon saying that is the insurance, insurance department denies that, then I asked to speak to tje manager on duty, he also gave me the sam excuse, and my answer was not ansered, after that, they just ignored my replies on facebook messenger, I then got hold of them on twitter, and was told that they will look into that, for me that is totally poor customer service, when tje manager spoke to me, I told him that I do not agree with his answer and jist put the phone down, really poor service.