Hi Timbo,
have you tried asking the credit card company to take up the problem. I know Barclaycard will as they are doing so for me with my dispute with Multi-region.Co.Uk.
Don't use them, found unbeatable to be great on delivery, never had to use their customer services, also same goes for SuperFi.
I find Richersounds to be good, at least thru my local branch in Cardiff.
As for customer service you won't beat John Lewis