Hi everyone,
I was just there today - It's right beside the Aman Bank on Gurgi Road (JUST past the bank if you are headed towards Souk Telat). If you are collecting something, you have to go down a ramp where there is an office for collection at the bottom. If you need to ship something, you have to enter the building and go up to the 2nd floor where you will find the office.
Good luck! 
p.s: Kazeem - I hope you got there alright, before it was too late...