It seems like a little troubleshooting is in order. If you are comfortable with working around electricity, then you can do this yourself. If not, DON'T, and hire an electrician. RVs don't necessarily need an "RV" service tech.
It seems to me you need to confirm that you have power properly coming from the generator. I would reset all breakers by fully turning them off and then back on. Even if they "feel" or "look" okay, they could still be tripped. Don't forget about the most important one on the generator itself. Then, you need to check to see if the transfer switch is functioning properly to automatically switch between the inputs of the generator and shore power.
Here are some videos to help you out:
I'm also attaching a wiring diagram and my Generac Guardian manual. Good luck! -Larry