Pick up of a rondom package

I requested my parcel to be picked up yesterday in Joburg which they didn't do. When I called today to follow up they said my parcel is already delivered. Turns out that they took a random parcel from reception even though I clearly stated under the "pick up instructions:" to "ask for Mareli at reception" which they clearly did not do. Upon investigation of a copy of the waybill I requested, there is no name or signature on the pick up side. So I have no idea what they took from reception or who gave it to them. So in short I paid for a service, gave clear instruction to ask for me upon collection and here I am with my parcel still in hand while they state its been delivered. Not sure what I could have done from my side to prevent this.