Advice on erosion on my backyard

There is some pretty bad erosion in my backyard specifically under the electric utility box. It is a new build that is ~2.5 years old. My backyard faces a creek which is actually pretty full with plants and trees, but this section between my neighbors house and mine is eroding pretty badly.

There was a retaining wall built across the neighbors next to me, but it stopped around 1/3 of my property since thats how it was designed. The city and county won’t help because that part of my backyard is in a flood plain and it’s considered “natural erosion”.

My neighbors house has a higher elevation than mine, and I believe that is where the water is running down when it rains. What can be done in this situation?