The campground "could" have control, but only if the primary power transformer belongs to them. This is not normally the case.
Check between the two side slots on the pedestal. You should have 240 volts. Then check each of the side terminal to the bottom terminal. They should bothe be within a volt or two of each other.
Then check between the top terminal and each of the side terminals. They should read within a volt or two.
If the side terminals to neutral and ground are uneven then the campground has a wiring problem.
If the voltages are within tolerance at the receptacle, remove the cover from your 120?240 volt distribution panel. Perform the same tests there.
You could have loose connection on the neutral. Could be in panel or could be in transfer switch.
