You most likely broke the plastic handle that operates the door catch prong. Slide something like a butter knife in between the door and cabinet to push the catch open. You can then take the door apart by removing four screws, to get at the broken handle. Watch out you don't drop the glass!
Alan
September 2011
I can answer this question...
How can l fix my LG Intellowasher 7kg door that wont open?
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Try fixfault.com to fix washing machines.