[Your address and contact number]
[Company/supplier's address]
[Date]
Dear Sir/Madam,
[Reference: order number]
On [date], I [bought/placed an order for] a [item].
I did not receive the item and on contacting you I was advised that the delivery driver had left the item [with a neighbour] [add details of the location where the item was left].
Under the Consumer Rights Act, the goods remain at your risk until they are received by me and I would request that you now make arrangements for the [item] to be delivered to me without delay and would request that you confirm that you will do this by return.
Yours faithfully,
[Your name]