Dishwasher not working properly

We bought a Defy Dish**** in December 2013 from Makro. The last few months it has stopped working properly, it doesn't clean well and we often have to do more than one wash per load. We have been in contact with the Defy office in City Deep, a technician (Alan) came out nearly 3 weeks ago to look at the machine, but merely rinsed and cleaned a few parts that we could have done ourselves, he also advised that we should always use the heaviest/hottest cycle which we have been doing. This has made no difference. I phoned Defy again yesterday as the problem has not yet been resolved, after being asked \what would you like me to do"by the lady on the phone I was advised that Alan would come out again today (21/04/15) to relook the machine. He never came nor did we hear from him. Our machine is still under guarantee and we would like this issue resolved before this expires. We still have our original invoice"