DEFY Ceramic Hob, No help from Makro

I bought a ceramic hob and an oven from Makro. I was asked to pay a R500 for insuring it. After a year the hob cracked across one the bigger plates. I called them and told them the problem, and I was told that the technician will be sent to me in three working days. No technician ever came, and it is more than 7 days now. I lost my trust on them. I even sent them an e-mail, but in vain. THEY HAVE MORE CUSTOMERS AND THEY DO NOT CARE ANY MORE. I NEED MY HOB TO BE FIXED IT IS ONLY A GLASS THAT NEEDS REPLACEMENT.