Who do I contact regarding Billing errors/troubles? DSL Extreme FAQ| Vist the DSL Extreme Billing Support Page. You can contact them by phone: Billing Dept. Hours: M-F: 6AM-6PM Sat. 9AM-4PM Phone: 1-800-774-3379 Fax: 818-902-5568 Or by the tools built into the Billing Support page by Bill edited by sashwa | ||