Personally, I would be hesitant about going with a company that gives no company details, no company registration details, no address, etc. on their website.
I don't know, but I would also question whether that's legal.
But if you really want to contact them, why not use the 'Call back' facility on their website on the Contact Us page? Let them pay for the call.
(I've used that once with another company and it was instant - it must have been automated and it also seemed to bypass the queue (if there was one at the time?).