Bad service

Discovery Insure running a competition with regard to spending a certain amount for petrol and stand a chance of winning a R1000 voucher. I received an email on the 28th of May informing me that I won the R1000 for petrol. Sent an sms as requested. Up to today after phoning them twice still no voucher. I have the email as proof. The last consultant (Wendy) did not even return the call after she said she would. Sorry but this is not good enough and still awaiting my voucher.