You did not mention if the other campers in your immediate area are having this trouble also. I would ask them and if they have the same problem they could report it also. If you can not work anything else out you can get a professional to take a reading and then provide the results to the campground management.
I recommend the use of the surge protectors that have built in power monitoring. The monitor will turn the power off to your camper until the voltage returns to a safe level. This works for voltage that is too low, as well as voltage that is to high. Some of these units also provide protection for an incorrectly wired pedestal. You can get the units that go inline with your power cord, or they make a version that mounts inside of your camper and is permanently wired into your power supply. No matter what version you choose remember to get one with power monitoring as well as surge protection.