Unprepared to handle a group booking

My friends and I had a group booking for 19:39 on Friday night. There was an incredible mix up and our booking was apparently cancelled (We are still to find out by whom). After making a plan to set our group up at a table we waited at least half an hour before ANYONE came to ask for our drinks order at least.In the interim I ordered my drink from the bar. The was ONE waiter for our group of about 20 people and the rest of the people on that side of the venue. A group of friends joined us at least 15 minutes later and they received their drinks before ours! Our food order took EVEN longer as the friends that joined us later had FINISHED their meal before we RECEIVED ours. This was my friend's birthday and we did not want to spoil it by complaining to management on the night and therefore i am laying this complain now! I am a regular patron of Buena Vista and am very unhappy with the service received. This has caused me to lose faith in the service and also doubt whether I should continue bringing groups of friends to your establishment! I am utterly disappointed.