This has happened a sveral times over the years, amnd I have manged to get a much longer life out of it without getting a repir man out. Once the pump was blocked, just refer to your manual for that.
The other times it appears to be nothing to do with the pump, it was something to do with a build up of something from the tablets. I spoke to friend who repairs them and he said pull it out and turn it on to its left side for 2 minutes, give it a little shake and then reset it , hey presto. Some water will come out so make sure you are ready to mop up.
This will save you some money believe me.
Matt H
February 2010