Vodacom don't keep promise.

The problem with Vodacom is that there is no customer care email address, the only way they respond is here. I don't know why they always promise you things that they don't keep. Iam this year 22 years with Vodacom and Nicolene in upgrades promise me a shopping voucher because I am a very good customer, when I inquire about it, I was told that I would receive it after 3 payments on my account and now after 4 payments still nothing. I don't know why what is the reason??