Waiting for an issue to be resolved since last hear

I got a call END OF LAST YEAR from a lady from Vodacom with regards to a change in my plan (a good one) due to my usage and being a valued customer. On my call I asked her so many times if my premium won't change and she said it won't so many times (mind you calls are recorded) I even got the confirmation via email and sms with regards to my change.. since then my premium increased from R400 something to almost now R700!!! I called Vodacome already more then 3 times and all I got was we will get back to you, we have to escalate this and we will have to go through the call logs (which I requested) I was told "someone will contact you in 2 weeks latest) and till date no calls and nothing has been done!

I have been with Vodacom for the past 10 years! And this is what I get. I need answers