you can buy 3m adhesive, but make sure the 4 latches are in place, if they are there shouldn't be any gap even without the glue.

hi Hassan,

it happened to me too. You need to fix the position of the little latch thingy first. Don't worry it's flexible plastic, it won't break if you're careful. Make sure the four of them are in place. I forced mine so hard, that the latch bent. Perhaps it's the same case as yours.