[SaneBateman]

As in title how to perform it with light item like phone case or watch band? Is fake item better than EB?

EB must be performed when the item you want to SE is about 120g or less.

If you try to "fake item" with whatever, Amz will most likely say that the item is not from their stock and will deny your claim.
Therefore I don't know what you mean about "fake item", but the WIR method (Wrong Item Received) is the way to go if you want to claim that you did not receive what you ordered.