India Post — Delay to serve a speed post

I have posted a urgent letter through Speed post of RMS Sealdah on 11.03.17. On tracking it is found that the letter is lying at Kolkata Airport. The letter is very important to me to reach at destination.Several times I have contacted with customer care of RMS Kolkata. Also I appeared in the office of RMS Kolkata.But no fruitful result is getting upto still.