Internal Error you need to resolve

I did an upgrade for a J3 Phone on the 19/09/2016 and have a receipt showing the date of the sale. Today I went to Telkom store in Pavillion Durban and I was advised I cannot upgrade as my upgrade date is still in the future. Some staff member did an update on my profile in December 2016 and for that reason my contract date was moved ahead by 2 more months. This is an internal error and it has nothing to do with me as a client and it should have been resolved internally. I want to do an upgrade now and this months is my 23rd month, Resolve this, it was an internal error and it is not my problem. Upgrade number is ********** . Upgrade is the Samsung J7 for R219 a month. Resolve this