Nokia 6233 — nokia service centre unable to deliver product on time

i m a user of nokia 6233 purchased one month ago. after using is for 1 month its speaker malfunctioned and stopped functioning.And now after giving it for repairing they are unable to deliver it on time. They gave me duration of one week for repairing and after one week they say they need more time. I dont know what the hell they did for 10-15 days. Please advice what action should i take against nokia service centre-Arya infotech, 81A S.P. Mukherjee Road, kolkata, ph-[protected]. My jobsheet no.[protected]/080404/38