How can I fix my Sanivite 3 as it's not pumping out the water?

...which stopped working mid flow. The unit is used to pump water from a washing machine in our cellar with the pipework from the unit travelling up some 5 ft into the main sewage/drainage pipe. There is a faint buzzing sort of noise coming from the unit and it is feels warm at one side. I have now disconnected from the electric socket. Could it be that the fabric softner has narrowed the pipes or clogged up the unit? Is this fixable?