[hvidgaard]

They often have you state particulars of the account details. MS will send you an email with a code that you must tell them.

In any case, one isn't more or less secure than the other. The physological effect of speaking to a phone just makes someone feel one is more safe. I'd say that if you send an email to the address you have on the account details, you can reasonably expect to get the right person to the same degree as you would when calling the phone number on the account.