E-mail us at GTQA@nicorinc.com and receive a response within one business day. Transportation customer service call center (630) 983-4040, Option 1. Call Center hours are Monday-Friday 8:00-4:30 C.S.T. Fax contract service - send and receive your customer contracts via fax. Daily Balancing Status (DBS) - receive daily usage, nom and storage balance information electronically. Transportation Customer Info. Database (TCIDB) - receive customers' contract and summary billing information. Electronic Billing (E-Bill) - electronic transportation billing, containing all the detailed billing information on our current paper bills. Electronic Payments - to be released soon. Please contact us via e-mail or through the Call Center to learn more about these services.