Account upgrade without my consent

I have picked up that my Monthly fixed service fee has gone up from R107 Elite to R209 for 31 Jul R209 and 31 Aug R209 a month and when I phoned the Standard Bank on the 1st of September spoke to Musambiwa holding on the line for almost 40minutes to dispute this and find out whats going on I got told that my Account was Upgraded to the Prestige package,WHICH I DID NOT REQUEST!!! I was told that I can't fix it over the phone and need to go to a branch with my Id to fix this and they will be able to tell me when and who changed my account and also refund me the overcharged amounts for the past two months of R204.00. But why???When I didnt request the change and who has access to my Account to make such changes that costs me Money!!! It is a concern and very suspicious as How does my account get changed without my request and now I have to take time off from work which I can't as we have been off a lot to go stand in a line at a branch and sort out and investigate something that wasn't authorized by Me!!!