Terminology is important.
Wire = SWIFT Wire = International Wire -> CCBILL doesn't send them anymore anywhere I think
ACH -> USA only
SEPA = "EU Wire" -> CCBILL still supports it, but this works only for bank accounts in the European Union. Also, it has to be sent in EUR currency.
There are a few extra European countries which also support it: Iceland, Liechtenstein, Monaco, Norway, San Marino, Andorra, Switzerland. (These countries are not part of the EU but part of SEPA.)
But UK is an exception. It was in SEPA because of the EU, but they still remained in the SEPA even after Brexit. So a SEPA transfer (EUR currency) to a UK bank account would work.
Maybe your customer service rep or CCBILL didn't realize this. They didn't update their FAQ either, they don't list UK in the SEPA list:
https://ccbill.com/doc/affiliate-faqs &
https://ccbill.com/doc/merchant-accounting-faqs