Hi, I sent an email to the address ("U.S. Visa Information Service (Canada Yatri)" <canada_contactus@visaops.net>) and explained my problem with screen shots of the process and issue. They got back to me in a few days. After a few back and forth, the account was set to pay the fees. Also make sure you selected "immigrant visa" as the choice on the Official U.S. Department of State Visa Appointment Service | English (usvisa-info.com)
Also see the Visa Application Payment Issues email in the Contact section of the ais service: Contact Us | Official U.S. Department of State Visa Appointment Service | Canada | English (usvisa-info.com);
Best wishes.
