Not sure if you have tried this but unplugg the washer and wait 2 minutes and see if you can open te door then.
If not then you need to give the door handle a good bang with the side of your fist and see if this shocks the door into opening from there.
If that doesnt work then its more likely a broken door handle.
To fix this im afraid you need to pull the washer out from under the unit.
Then remove the top panel.
Make sure the washer is unplugged.
Then look down the front of the washer on the inside on the right hand side.
There you will see the door lock. You need to reach down in there and feel the far left of the lock and there you will feel the metal door pin. You may not see if but you will feel it there.
You need to push this door pin to the left and at the same time pull the door handle and it will open from there.
Once you have it open you can then check the door handle and if snapped you need to replace it from there.
Try that and see what you find. If you need anymore info just get back to me.