Task: Classify the mental state of the tweeter based on the tweet, determining if it is 'neutral or no emotion' or characterized by any of the provided emotions (anger, anticipation, disgust, fear, joy, love, optimism, pessimism, sadness, surprise, trust).
Tweet: @bt_uk why does tracking show my equipment delivered, when it wasn't? Why is my service suddenly delayed? We've already 3 weeks.
This tweet contains emotions: 
anger, disgust, sadness