Builders Warehouse desperate for money.

Some time back I placed an order with Builders Warehouse, their reference ***, and they promised delivery within days. Over a week later with no sign of the goods and no explanation of why the delay I cancelled the order with the idea to get my monies refunded. It is now days later and despite a number of emails to them I am no closer to a solution. They have offered credit note when in fact what I want is my money back.