COMPLAINT against speed services couriers.

I sent a parcel via speed services couriers on the 21st of December and I was told it would reach the destination by the 23rd. Till this day they haven't received the parcel, what's worse is that even at the post office they say my tracking number doesn't give them any details! I tried calling and emailing them with no luck ... can they please just return my parcel to the address I'll find another of sending it!