[AC Question]

I linked my school email to the email app that comes with the galaxy tab s 10.1. Whenever I receive an email I read it and delete like normal then about ten minutes later I receive the same exact copy of the email I just deleted. This happened with a couple emails that I've gotten but recently I've deleted the same email 8 times so far and I know for a fact that I know that the person only sent the email once to me. I was wandering if there's a way to stop this from happening.