QVC would collect a bulky or heavy item like this if you want to return it; they'll confirm this if you order via the 504030 number.
Candycane, contact CS again and offer to email them a photo of the post office receipt (without sending them the original) and ask whether you should do a charge-back via your credit or debit card. On the whole companies don't seem to like charge-backs so this suggestion has worked for me a few times, most recently Asda sent me a £10 gift card with an immediate refund at the merest mention of a CB. :mysmilie_59:
If you sent it "Signed For" there'll be a 16 digit code but the service isn't tracked per se; it can only say whether or not it's been delivered. An ordinary "proof of posting" from the post office will only show the destination email and details of the time date and weight of the package along with the destination address. I've been selling on ebay for 15 years and never successfully claimed the full cost of a lost item (even when I could prove it was lost in their system; the best I've had is a few stamps so I'd pursue QVC before Royal Mail as the easier nut to crack IME.
There is definitely a 16 digit code on non-Signed For Proof of Posting slips, Akimbo. I have one in front of me from yesterday as I posted something I had sold on eBay, just ordinary second class. I have always had success with my rare Royal Mail claims, I must say. (Hope I’ve not jinxed myself now!)