Order shipped with missing items

I Ordered 5 Items

2X Office Chairs and 3X LED strips and to ensure that the delivery date was a date when i am available to receive the above items i payed Guaranteed shipping

The items were delivered today as the Guaranteed date of shipment (note that this was at an extra cost)

upon accepting the delivery there was an item missing, the 1X chair

i asked him where the missing chair is and he said that the delivery note only states that he must give me 1X chair and the 3X LED strips

TAKEALOT PLEASE advise as to what i must do as to the missing stock and the Guaranteed delivery payment

Order Number #***4