The most common cause of the problem you describe is , worn out carbon brushes on the motor.
It's a bit awkward to check/change the carbons on the motor without opening the machine up but, if it has an open base, you may be able to do it with the motor in situ.
You'll need a torch for this. Unplug the appliance first.
Tilt the machine rearward, have someone hold it for you.
Don't turn it upside down or lay it fully over.
You'll see the motor and the carbon brushes in their holders.
Take the holders off and check the carbon brushes.
The holders will be held by 2 screws or 2 5.5mm bolts.
If the carbon brushes are worn out, you'll need to obtain and fit new ones.
Assuming no other problems with the machine, this will get it going again.
If you search on Ebay for Zanussi carbon brushes this will bring up pictures of what they will look like.
If you decide to purchase them there, please check with the seller that they fit your machine.
Check it out, get back to me if you need more help.
Obviously, if you cannot do the work yourself, you'll need to get someone in.
Hope this helps
Let me know how it goes