Delivery issue, DP World

I was given a date for delivery which was different as in a day earlier, when I would be in. Now just received automated email to say will be delivered the next day & cannot change anything as in day, time, leave with neighbour. Neither Dell nor DP World have any means of contacting them. Dell just keeps circling to my order & DP World is just a form, blank. Not great, I was going to change delivery date but Dell said would be delivered day I would be in, even so no way of contacting either company. Pretty poor in this day & age when even the Post Office can now track & change deliveries.