Okay, you know that she signed for a bunch of parcels but there is no official method to trace a parcel once it came into the company.

Is there one specific person who would be making these deliveries? Since it just came in, would it be possible to talk directly with them to see if the remember if it was delivered to someone else that day...

I am actually a little surprised that the seller would have an incorrect phone number for you. Given the amount of money it was worth, you would think that he would want to be able to contact you if something went wrong...