Sounds like you are not following the instructions. There is no call
to you.
The web portal gives you a code. You dial **5 followed by that code.
Also, it is not unknown for Obihai's server to go on the blink at a weekend and not work properly until someone reboots it on the Monday morning.

If you can make the **9222222222 and hear your own voice it is very unlikely that your OBi200 is faulty.