Understaffed causing very, very slow service

I called my local Denny’s location (Royal Palm Beach, FL) to advise them that I would be bringing a group of about 15 people there for lunch. We do this once a month and the number of guests does vary from time to time. I called a day ahead of time and was told to only call the actual day that we would be there. So, I did that. When we arrived we found that the back area where we sit was dirty (tables not cleaned), no set-ups laid out, no menus on the tables. We cleaned a couple of the tables and sat down. The one server there eventually took our drink orders. After what seemed like a long wait this same server started to take our food orders. I was there for almost an hour before she got over to where I was sitting with 2 others. After about 30 minutes the food started to arrive. It came out of the kitchen quite slowly. It took a very long time to get our food. After about 2 hours there were still a few of our folks who had not received their meals. That’s absurd!! The rest of us were starting to leave and then the missing food arrived. Too late!! The idea is for us to have a meal together. The server blamed the problem on the cook. Apparently, he had some sort of attitude. I’m not sure what that was about. Our late-eating folks rejected their meals as being served way too late. They were very, very upset. Upset to the point of suggesting that we never come to that Denny’s again. The rest of the place was not busy so food timing should not have been an issue. We didn’t blame the server. She tried to take good care of us. The whole experience was a disaster. Denny’s can, and should, do better. The young lady who was the manager had no clue as to what was going on. No one else on the staff bothered to try to help with this issue.