Hi,
First of all welcome to the site (and remember there are no bad questions)!
If by "free WiFi" you mean WiFi in Starbucks or the like, it could very well be that the router is configured to not allow client devices to talk to each other for security reasons. This would kill your attempts to share data between the PC and the phone. I would try this on a private network where you know that clients can "talk" to each other. Remember that a lot of home routers also block this traffic by default so you may need to login to the router and check the settings.
To be safe, if USB cable is not working for you (which would be odd because 90+% of computers have accepted my phones) you could always fall back to using an SD card to transfer the data. This of course assumes that your telephone has an SD card slot. If your phone is not so endowed, you could try a small USB stick and a USB OTG cable (that allows connecting USB devices to the phone). Again, your phone will need to support USB OTG, but I would expect any non burner phone produced in the last few years would do so. Note that USB devices that take a lot of power to spin up will not work (the power has to come from the phone) this is why only small devices are likely to work.
Good luck!
Regards,
Eric.
