on what I thought must be a technical issue.
Did you choose the "problems with service" (Option 2)? Might be better to try "Billing & account queries" (Option 1).
Otherwise all you can do is lodge a formal written complaint saying that as the account holder they agreed to supply you with BB and that they have broken this agreement by ceasing the service without any valid reason.
They said your a/c no longer existed. Have you looked at your Member Centre ( https://membercentre.orange.co.uk/MCPres/
) on their website to see if it's still there?
1999: Freeserve 48K Dial-Up => 2005: Wanadoo 1 Meg BB => 2007: Orange 2 Meg BB => 2008: Orange 8 Meg LLU => 2010: Orange 16 Meg LLU => 2011: Orange 19 Meg WBC