Customer service sucks 😈😈😈😈

I have signed up with RSA WEB in May with a promotion that they were running if you sign up before June the amount was R349 for 3 months and then you will pay the normal amount of R639. On Wednesday I received my router and was live on Thursday I checked what my bill was and its was R833 something like that so I was chatting to the online agent where he advise I needed to email them which I did and up until now no response from them I am so angry and frustrated that they dont acknowledge your email nothing im ever so sorry I signed up with them really