updating credit card info

Hi - been trying to update my credit card info on the Zoom site.  We are located in Canada and Zoom's system will not accept the change.  Keeps indicating a province needs to be identified but drop down menu is only US states.  Have been through all the help screens and even tried to set up second back up credit card with no success.  Tried to work through their chat support. Spent a hour on hold on the phone.  Any suggestions?