Cannot find my parcel

Dropped parcel on 14 Dec in drop box. Started following up on 17 Dec as I cannot track the parcel. To date I have been told they will investigate. Still no tracking still no response or investigation that I know of. This is the 1st time that any courier service delivers such poor service. Hell just tell me did you or did you not collect the parcels from the drop box. If you did where the hell is it now? If not when will it be done.