Anyone have any experience with controlaccount.com debt recovery agents?

As above these guys have sent me a request for money to cover import duties paid on my behalf by Fedex

I imported a Satellite receiver from China, which was faulty, so was immediately returned.I rang Fedex and also the Revenue about the duty.Revenue said that if I returned it, Fedex need to contact them for a refund

I sent a copy of the receipt for the returned item to Fedex as they requested, then a few weeks passed where I didnt hear anything, and then I get this demand for payment from controlaccount.com

I called controlaccount and the guy on the phone was very condesending and confrontational, kept blabbing on about some agreement between all couriers and the Revenue.I couldnt get a word in edgeways with the guy

Anyone else dealt with these before?