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Did you submit the same restaurant again after it had been accepted?
If you can give us the gps coordinates (they are shown below the photos in the email you got when you submitted it) then we can check the map to see what is going on there.
I found the accepted nomination on the map:
It is not a Pokestop because there can only be one per each of those boxes in my screenshot. The pokestop in this cell is Telefoman
The other nomination will be rejected as a duplicate.
This will explain in more detail what has happened: Why an accepted Wayspot may not be used in Pokemon Go (S2 cells and Pokemon Go)