I am sorry to read this and to add I have never heard of this shop.

I note no UK phone number has been listed ... it might be worth while doing a whois on the domain.

You need to tell them on the phone what the problem is and ask them to correct and send proof.

I am not sure if you guys are protected from the Distance selling regulations we have in the UK.

If you search, in the UK we have trading standards and they that might be able to help.

As a first port of call I would call one of their UK supplies and find out who they are. So try Schumacher.

If that does not work look on the BRCA site and look up the contact details of the club they list. I would then contact the secretary of the club and see if they can help.

Good luck