Really bad service

I am trying to cancel an order. This is proving to be absolutely impossible. You cannot get through to them on the phone and no-one responds to emails. To make matters even worse their Facebook person says I have to use the Online Returns and Exchanges form - this does NOT work for cancellation of an order not yet delivered - if so it is so incredibly obscure and completely lacking any intuitive interface that I cannot find any way whatsoever to cancel an order.