Non delivery of gift

As the items I ordered online were a gift it was critical for them to be delivered today hence my selecting the first time slot of the day. When the items were not delivered during the allocated time slot, I contacted the Call Centre. The consultant promised to call me after establishing the reason for non-delivery but didn't do so. I then sent an email to the address on the invoice but received no response. I cannot claim a refund as I do not have a copy of the dispatch note. Now what?