Shell T-card

I was given a Shell T-card in October 2020, with the promise of getting back 25c for every litre of Shell Diesel I use. I have done more than 30k km to date, which equates to thousands of Rands in refunds. The problem I have is that the guy who is supposed to come with the cash refund does not answer his phone, he only answered once, that was when I registered the t-card, ever since then he does not reply on Whatsapp messages, he does not answer phone calls, he also does not return phone calls, which leads me to believe that he, Christo is his name, is busy *****ing my money. So, this is a effort to get him to own up and contact me to organise the promised monthly payments.