Is it possible you have a 2nd email address 'forwarding' emails into your main inbox?
If you could check who the recipient is on each both of a set of duplicate alerts, it will show you if it's the same email address or 2 different ones.
Please let us know so we can further advise you what to do.
Is this still happening? Can you please tell us which emails in particular?
Found out it was only happening at work. Determined that my email rules got duplicated. Problem is solved.
Note - I replied back directly to your email on 11/20/2017.
Customer support service by UserEcho