We had lunch for a group of 18 adults and 5 kids a...

We had lunch for a group of 18 adults and 5 kids at DAHAB restaurant. We had guests coming to Qatar for the first time.
We agreed to have a set menu of barbecue with appetizers, soft drink, and coffee.
The restaurant has a nice view.
The quality of the food is good.

BUT, The barbecue was served on shared plates. And was not as agreed, they only served for 14 persons. After checking with one of the waiters, he confirmed that the quantity was less, and we can have more if required. He said they did that, so no surplus food we wasted. But, simply, a set menu is a set menu.
Then the restaurant manager said that he well serve the food because he is GENEROUS only. I couldn't believe my ears.
I strongly recommend the management to give Etiquette training to that person.