Refusal to compensate for missing item from delivered parcel

<div>I ordered 2 sets of blades for my Philips shaver and paid in advance and in full for these . The properly sealed parcel was delivered by a courier outfit and signed for by a house-sitter as my wife and I were out of town on that day. Upon opening the sealed parcel the next day it was found that only one set of blades was included. After some emailed communication with S&amp;H that company refused to send the second set or refund as requested. It was pointed out that the person receiving the parcel should have opened and checked the parcel there and then. It was also pointed out that the company's quote and acceptance had stipulated that deliveries should be fully checked before signing for the parcel. Upon pointing out per email to ***** of S&amp;H that such a procedure is impractical in the face of a delivery truck with engine running, I was informed that checking in detail was mandatory. Refusal to comply with my request was repeated.</div>