Pay Bill Online Bill Pay Make a One-Time Payment MDI offers three options for fast, secure and convenient bill payment solutions Online Click to make a one-time payment.Bill Pay » By Mail Mail your payment (including invoice number) to: MDI Attn: Accounts Payable 3501 Broadway St NE #100 Minneapolis, MN 55413 Phone Call customer service: 651-999-8205 or 218-313-1723. Please have your invoice number and credit card ready.