Ascension Saint Thomas customer service. Ascension Saint Thomas Rutherford and Ascension Saint Thomas Hospital West: 615-222-6638 or 800-242-7416. Ascension Saint Thomas Hospital Midtown: 615-284-5340 or 800-489-5604. Ascension Saint Thomas Hickman: 877-664-4076. Ascension Saint Thomas River Park: 800-725-8420..