Security :: Microsoft 2 Step Verification - Unable To Add Phone Number

I have 2 Microsoft accounts. I have enabled 2 step verification for both of them. With one account, I was able to enter my cell phone number to complete the process, so I would receive a text message if a device I haven't set to trusted tries to log in to that account. I tried the same process on the second account, and whenever I try to enter the same cell phone number, I get an error page that the service is 'temporarily unavailable'. I have tried every combination of entering the cell phone number that I can think of, and nothing works for that second account.

With the first account, I was using the Opera browser to enter the information. With the second account, I was using IE 10. With the second account, I get an e-mail with a verification code if an untrusted device tries to log in. This is OK, but I would prefer to receive a text to my cell phone instead, as I do not always have such instant access to my e-mail account.

Or can you not use the same cell phone number for 2 accounts?

Edited to add: This is the exact message I get when I try to have MS send a code to my cell phone:

There's a temporary problem with the service. Please try again. If you continue to get this message, try again later.

I've been doing some research online this evening, doing a search with that message. It looks like this is pretty hopeless. Once people see this message in relation to any MS services, there seems to be no solution for it. I guess I should just be grateful that I at least haven't been locked out of my Windows Live account entirely, since Windows 8 is so tied to being able to connect to one's Microsoft account. Of course, the account I use for my throw-away Hotmail account works just fine.

The format I've used for the phone number is (XXX) XXX-XXXX . I've tried variations of that with brackets, spaces, and hyphens, nothing works, but at least e-mail verification still does.