Bad Service after the sale and not correct selling tools used

I opened a checque account at Nedbank Savvy, the guy said if I opened this account I will receive R200 cash back for the remaining term that I pay for my Car Finance at MFC, this is now the 2nd months still no cash back and I just dont get this sorted out. First he told me its because I must use the app, which I also doing since last month. I DONT KNOW WHAT TO DO ANYMORE, THE AFTER SALES IS JUST USELESS