I had originally reserved a campsite in the Coyote loop, which had been advertised as a non-electric site that could accommodate either tent or trailer camping. When I got there, the sites were actually walk-in tent sites, and most of the sites were missing their number markings. In general, the area looked like it wasn't being maintained and things were falling apart.
I ended up making a new reservation in the Cholla electric loop. It was much better than the Coyote loop and the sites were well-maintained. However, there was no camp host available, at least while I was there.
Cancelling my original reservation wasn't possible on the website or through the call center, which was pretty frustrating. It doesn't make sense to me, since otherwise the website seems very user-friendly. The call center rep was able to submit a cancellation/partial refund request and gave me the contact info for the park ranger office that would take care of the refund for me. Even when I called the office, I wasn't able to speak with the individual who could take care of the refund, but the office rep that I spoke with was friendly and did pass the message on. It took about a week and a half before my refund request was finally processed, but I have received the email confirmation that the refund is processing.
Overall, the system seems inefficient, but everyone I spoke with was very nice and professional. And in the end, everything worked out and I was able to camp at a better site, so overall it was a good experience.