We're sorry to learn if the same thing happens, JurateNair.
When you are at the Sign-in screen, do you see OTHER USER at the lower-left corner of the screen?
If you do, click it and enter your email/password of the Microsoft Account you created, instead of the phone number.
If you're still unable to sign-in, we suggest to do a reset on the device.
At the sign-in screen:
- On your keyboard, press the Windows logo key + L. If you need to, dismiss the lock screen.
- Hold the Shift key down while you select Power > Restart in the lower-right corner of the screen.
- After your Surface restarts to the Choose an option screen, select Troubleshoot**>**Reset this PC.
You can check this page to be guided as well: https://support.microsoft.com/en-us/help/4023533/
Once you've reset the device, you can start from scratch and make sure to enter your email and password for your Microsoft Account when setting up the device.
We hope this helps you out.
Regards,
Janette_Z