I wrote this topic about the inclusion process: Why an accepted Wayspot may not be used in Pokemon Go (S2 cells and Pokemon Go)
If it would help you understand, you can leave the gps coordinates of one that didn’t become a Pokestop and I can try to show you the S2 cells there.
Edited to add a screensnip of where you can find the gps coordinates in the submission acknowledgement email if you still have that:
