cleanliness and food availability

And what did the manager say when you pointed out these atrocities to
him/her?

You *did* voice your concerns to the manager *before* asking for a
refund via a third party website, didn't you?

This is the sort of thing that should have been brought to the
attention of the manager. You should have refused to pay until the
manager came to you table and made some sort of effort to apologize or
remedy the situation.

You pay BEFORE you go through the buffet, at least at the GC's around
here. So there is no way for one to withhold payment. A refund is in
order in this case. You've already paid before you get the bad service
or dirty food in this case...

unfortantly you have to pay wheen you walk in the door, before you
even sit down to eat.