False Advertising on contracts deals

I recently upgraded 3 of my 5 contracts.

On my last number upgraded, i was told that would receive a R2000 Zando voucher.

I have been liaising with sales representative for the past 3 months to claim this voucher and all i have told is that it was registered. I know that it was registered, however no voucher was provided. On my recent query, i was then emailed the MTN invoice, as opposed to the actual Zando voucher. I have responded to the sale rep, and enquired what i need to do with the invoice, and its been another week with no response.

The reason for me upgrading to a more expensive contract was based on the voucher as well as extras that came with deal.

This is proving more time consuming and ridiculous as i been back and forth for the past 3 months.

I have been a loyal MTN customer for over 15 years furthermore, i have 5 contracts, yet the service i receive it really not worth it.