Contract Upgrade

In June 2014 Telkom Mobile offered me to switch my price plan on a contract which was in its 3rd year at the time, due to my high usage of data. I was told that it would not affect my upgrade since I was not receiving a new handset with the price plan change. I now cannot do my upgrade because I'm told it was done last year, the store refers me to the call centre, which twice insisted I wait for 5 days. It is now 11 days and when I send a follow up email, the agent does not even know what I am talking about...