Gedcom export to Familysearch

You should first check your GEDCOM to see if your download is correct.
You can only export a max number of profiles (depending on if you are a Pro user or if you are a basic user depending on how many profiles you added) and you can only export from a profile you yourself added.
See also How can I export my GEDCOM?
The export will also export any tree and/or data conflict, so you should try to solve those before exporting.
If you need to export more profiles than the max. number Geni will export for you, you can export from any other profile you added to the tree and combine the GEDCOM files (you will need a program for that, so you may have to Google for that).
If your GEDCOM is correct try contacting Family search support to help you further

Geni is a shared tree and that makes it more complicated. When you are connected and would download your tree you are speaking of about 180 million records.