TL;DR - Please remove the SMS requirement for removing/unlinking phone numbers for Battle.net accounts.
I linked a phone number to my account over a decade ago (O.G. WoW). I still have access to the email address, but changed phone numbers back in 2017. Currently the only way to remove a phone number is via an SMS message to the number you’re trying to remove? This wasn’t very well thought through by Activision/Blizzard.
I understand using an SMS to verify adding a phone number to prove it is yours, but there are quite a few reasons for phone number removal that involve a lack of access to the outgoing/old phone number. Furthermore, all of these old and inaccessible phone numbers remaining connected to accounts that cannot access them is only exacerbating the problem for current owners/users of said phone number.
Telecom companies will usually hold a phone number in reserve for a given period of time after account termination/change in case you change your mind, legal reasons, etc. That period could be a few months, a year, or more. After that timeframe, the number is put back into the “available” pool for re-issuance, as there are a finite number of phone numbers per Area or Country Code. I currently have a number assigned to my account that hasn’t been mine for years. If the new owner of that phone number tried to add it to their account, they would receive an “already in use” error, which wouldn’t be accurate. That’s currently an unsolvable problem, and would be especially frustrating for the new phone number owner since it is legitimately theirs, and changing to yet another new phone number is a not only a pain, but in many cases costs money to do so, and there’s no guarantee the new phone number (that likely used to belong to someone else) isn’t also linked to a forgotten Battle.net account.
Please Blizzard, remove the SMS requirement for phone number removal. It can’t possibly hurt, and may even help by reducing helpdesk work hours (i.e. save you time and money), and will also prevent customer frustration.