Lost parcel

Had a parcel out on the 14th and today parcel is said to have been delivered. I did not get my parcel and these guys take long to assist with a query. All communication is slow except for phone lines which are answered. Support will either put you through to someone that won' t answer or says that I should check with Security. How is a parcel delivered without any communication and how does it stay with security without a pin? My parcel is nowhere to be found and I am still waiting for answers. Bad service