You most likely don't have to go to the embassy, you just have to pick the one that's closest to your location (or where Tunisians usually apply) for the e-visa system.
Turn your phone sideways to see more options. This happened to me too and I couldn't see the option to go back and pay for my first application until I turned my phone sideways.
If you're using the owners of this group, it's legit and it works. It's not 100% if you have a bunch of fake education visas or other noticable offenses in your passport.