New accounts won't accept domain name with a hyphen

We’ve just returned to Virgin as broadband & tv supplier after about 3 years. 
In trying to register our new account Virgin is refusing to accept our email address because the domain name includes a hyphen (minus sign). This is a Virgin bug as the official definition of an acceptable domain name (see RFC1123) includes the hyphen as a valid character - and our email WAS accepted when we’re used to be a customer 3 years ago.  The validation has clearly been updated, wrongly.
If a virgin person spots this msg please escalate the fixing of a really basic bug so we can register our account and pay our bills! 
Thanks. 
Kind regards, 

Tim