Unable to add Communication Credits to an existing customer client but also on a brand new tenant

TechT1410 It took a while for Microsoft to get the Tenant to switch back into Legacy. Once they did that I was able to add the Communication Credits.  It took about a month for this to happen (resolved around 9-28). I was talking with the Microsoft tech a few times a week to get it done. There was some steps on their end to made it happen. What seems to do the trick was running Microsoft Problem Step Recorder and grabbing source code of the Office 365 page admin page from my web browser. I don't remember the details of the source code grab, but after I send them the files, they got it worked out.

I had the same experiences as StanStanford. It seems to me that Microsoft was moving towards a subscription on Azure to handle this, but totally forgot about 800 numbers.  I would hope they work it out soon. Hopefully you can have them convert back to Legacy so you can add the credits.