OMC Patient Accounts can be reached Monday through Friday, 7:30 AM to 5:00 PM (except on holidays), at: tel: 507.287.2780 toll free: 866.287.2780. fax: 507.287.2740. Mailing address: Olmsted Medical Center Attn: Patient Accounts PO Box 5777 Rochester, MN 55903-5777.