Bad Bad Service

Disappointing service. I have been struggling for months to get a billing issue resolved (payments are made via debit order) and my services keep getting suspended. They apparantly have a 'billing department' with absolute no contact details. I have been sent from pillar to post without any answers, the customer services department do not even have the courtesy to respond to an e-mail. I am so fed up with this. Going to a branch is also useless.