DirectAxis never stops email me

In their marketing emails this South African company doesn't ever allow one unsubscribe from the relentless marketing. I have sent emails to the addresses in the marketing emails, but they simply ignore them. I have just tried calling their (so called) Customer Services number and the person just placed the call on perpetual hold. I eventually got hold another person who listened and took down my details but I'm not holding out much hope. I will give them one more chance, and after that I will report them to the Financial Services Ombudsman.