Unhappy customers

We ordered food and there is a promotion for free desert,so we didn't understand that even if you order for many people you get one dessert,the promotion does not specify that and we phoned the call centre to get clarity and 2 agents that assisted us were rude.Order no ***.We really don't appreciate the service that we received and the terms and conditions for free dessert that are explaining that even if you order for many people you get 1 dessert free.