Website & Phone:
I have written (recorded delivery, e-mailed) and phoned them. I don't believe that it is a coincidence that my experience has been exactly the same as the previous post – my experience has been that Corvus offers relatively low ticket items which the company does not have and cannot deliver – and then hoping that the customer will forget about the promised "refund" which never turns up. I too have notified trading standards.
I have written(recorded delivery, e-mailed, called(the receptionist cannot deal with refunds! I have to speak to the manager'Gary' who is never there and never rings back!) i have taken advice from trading standards and will pursue it that way.
But please be warned and pass this on to as many people you can!