I lost my debit card or it was stolen, how do I get a new one? If your debit card was lost or stolen, please call us at 800-328-1935 (24/7). For international callers, contact us at 773-462-2000 (24/7). You can also report a lost or stolen debit card by logging in to your secure Alliant online banking account or the Alliant mobile banking app.