Hotpoint WMUD942P Washing Machine

This is my third replacement, No1 caught fire. No2, took engineers four weeks to find out the problem they finally took the back off it and agian this machine was black inside with smoke. No3 I got in April 2013 will not always spin, changes cycle on it own, and is noisy than when I first got it. Just phoned Hotpoint and as usual more interested in telling me I'll have to pay £110.00 if the engineer can't find the fault, I told the guy that there is a fault with the machine his answer to that was how do I know as I'm not an engineer, Funny though how I told the engineers working on machine No2 what the problem was but not before they changed the pump and the circit board. The guy then went on to say I need to add a chemical to the machine to keep it in good condition and low and behold you can only buy it from Hotpoint.