Defy dishwasher - Does not clean dishes

I have had my dishwasher since September 2014. From the beginning it left a sandy residue on my dishes. I kept thinking it will improve. Eventually in Jan we had a tech come have a look. He said there is nothing wrong with the machine. Now, in June it bombed out completely, could not switch on and tripped all our power if you plugged it in. I phoned Defy to come collect their machine and complained about the tripping and that it does not clean my dishes. The tech came in while only my **** was home and fixed the tripping problem. I had no feedback from Defy after the visit. I phoned (at least 6 minutes on hold) and complained again. Their excuse is that I do not pack it correctly. I had a nice lady from Unilever phone me to tell me to try pack it differently. So now I need to give it a week and give her feedback. So, now, on my Saturday morning, I sit re - washing the dishes that have already been washed by my Defy. How difficult can it be to pack a dishwasher? Glasses on top, plates at the bottom. I even rinse my dishes before the time. My sister has a Bosch and packs her dishwasher with unrinsed dishes, and they come out sparkling. Choosing the Defy over a Samsung wast