Poor Service from Defy Service Center

I have been trying to have my tenant's oven repaired. The service agent was out twice . Oven not heating after the repair. Reported back to the Service center got another job card, but nothing has transpired. Godfrey the agent cannot keep to his appointments. Tried calling Defy on *** call just rings. Sent email to service @defy.co. za not even an acknowledgement of my complaint. No problem in receiving the invoices for the work done. Immediate payment was made for previous repairs. This service is disappointing as I have been using Defy products for over 45 years.