When we reserved a specific site at a beach campground in San Diego we paid extra for a specific site, months in advance. We were called later and ASKED if it would be ok to move our site and a new specific site was offered. It was explained at the time that a group wished to be together. We were also offered a reduction in our rate for our inconvenience. We accepted. This is probably how it should have been handled. Since you wish to return to the park, I would voice my displeasure to the park managers/owners, so they understand for future reservations you have expectations.
JMHO