Unfortunately the model number you gave does not come up in the system.
However I expect this is a microwave oven, correct?
If the child lock is off but the door won't open then there is a problem with the mechanism and it will require a repair.
First, unplug the unit before any work is carried out.
Remove all the screws in the metal sides - you may need a special screwdriver for this, depending on the model.
Once the metal sides are removed, you can manually release the door from the inside.
If the latch was simply stuck, it may need some oil to help it move freely again.
If the latch mechanism is broken, it will require a repair.
If you are unable to carry out this repair work yourself, let me know your zip code and I can advise a repairer in your area, or alternatively you can return it to Walmart to see if they can help.
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Otherwise please reply back if you need further assistance.