Maybe a bit late in the day but... I had the same problem with HDN/Yodel a while back. Eventually got the direct line number for the depot from a facebook page setup by other "disgruntled" customers.
Yodel/Home Delivery Network
Carrwood Rd, Chesterfield, Derbyshire S41 9QA
Tel: 01246 260142
Rang them with the tracking reference number from my email confirmation, they found the parcel and I picked it up from the depot half an hour later. To be fair, once I'd found a way to speak to a real person they were really helpful