pathetic service and non responsive

My washing machine is 6 months old and stil undrr warranty after defy had to replace my previous one because it was faulty. So this machine stoped working about 5 weeks ago and I have reported that to the call centre after that it took a week for someone to come have a look at the machine just to find out that the part needs to be ordered so we waited another week. The came to put in the part however that part and problem was not diagnosed properly so they had to order another part for thr actual problem. Its bren 2 weeks now. When I call no one helps me and when I do get to a manager they will call me back which they never do. What should I do?