Speedpost — non delivery / delayed delivery of speed post

I booked letter by speed post (Speedpsot tracking no er[protected] from jaipur gpo on 29th december 2018 for mhrd shshstri bhawan new delhi, the sid letter has not been delivered to the destination till 2.) pm on 4th janaury 2019.
Since this letter was very urgent and was supposed to reach atleast third day m th delay / non delivery has caused me much metal tension and loss of a great opportunity. Advaice the necessary step to be taken aaginst the post al department.