If it isnt draining completly theres a 90% chance it is simply blocked, its only a common problem cos people DON'T EMPTY THEIR POCKETS! (i see this quite often infact did this morning) chances r u eitha have a bobby pin jammed in the pump propellor or a 20 cent coin acting as a butterfly valve in the tubing jus before the drain pump 20 cent coins fit perfectly through the pipe work but stop on the drain pump intake and can open and close letting water out sometimes then closing on others, if your any good with pulling stuff apart just remove the rubber piping coming off the bottom of the tub normally just a ring clamp and check for blockages and also remove drain hose and look in the hole and stick a screw driver in the hole and try turn the propellor round