So the next question is about the male and female flowers. For how long have they been producing flowers? Are there male and female ones? It is typical for cucurbits (squash, pumpkins, cukes, etc) to produce only male flowers for the first couple weeks or so.
If there are male and female flowers, you can hand pollinate some of the females to be sure they are getting pollinated.
Otherwise, if you think all this is working tell us some more about the weather, the conditions they are growing in, soil, fertilizer, water, how you have been caring for them etc and maybe post a couple pix and we will keep working on figuring this out with you.
(See also https://www.helpfulgardener.com/forum/viewtopic.php?t=38783 for people's similar issues with pumpkins)