Why is my Switch not charging?
Was your Switch out of charge? If it completely runs out, then you'll have to charge it for a bit before you can turn it on. When you charge it while it's completely out of charge, you will get no visual cue indicating that it is charging, until it has enough to turn on. Try leaving it charging for a few minutes, then check if it has enough charge to turn on.
If you still can't figure out why it doesn't seem to be charging, try taking it back to the game shop to see if they can figure it out.