If they've opened a case for item not as described, you will have to accept, and refund within 3 days, or send a paid tracked return label, and refund when you get the item back, you'll then have 48 hours to do so.
As it's obviously not working if you wish to relist it , you'll need to say it is not working, not sure if it makes it a saleable item, some might want it for parts ?
@simokellawa-0
