This morning I am getting the following message "This account is on a deprecated billing system. Contact Support to move it to the new system." when I open my subscription blade in the portal. When I try to submit a billing support ticket it just hangs while trying to bring up a support plan, which should not be necessary for a billing question anyway. For now it appears that the subscription is still working, but this seems like it will go badly. Please advise.
Looks like there is an outage in Azure: https://twitter.com/AzureSupport/status/1036970068058562560. All you can do for now is wait.