Payment of remaining tab balance

Hi! My wife was using Koodo and she signed for a plan where she got an iPhone 6 by the monthly tab for 24 months. She had to come back to our country and cancelled her koodo plan, paid her last december monthly bill but since the 24 months haven't passed yet we still need to pay the tab balance for the phone. We've contacted Koodo Customer Service and the employee said the total amount we needed to pay would be in the Koodo Self serve billing account, but some days have passed since then and still no tab balance is shown. We need to pay the tab balance as soon as possible. I'd like to have some help or tip to solve this concern, if someone knows how to deal with this I would be really grateful! Thanks and best wishes for 2019!