The process of changing phone servers.

PHK

https://forums.moneysavingexpert.com/discussion/comment/82073784#Comment_82073784

PAC by text is not mandatory in every circumstance.

If you have more than one line on the account, then you can’t get a PAC by text. You must either go online or phone. (This is so that people understand the potential consequences of cancelling one line - the service provider has to give you certain details that wouldn’t fit in a text message)

If the line is bundled with another service, then if the charge for the other service would be impacted or that service would be cancelled then you generally need to call (in some simple circumstances a link can be sent which points to a page detailing what happens)

If it is a business account then it falls outside of regulation and the provider can insist on any method of contact and make a charge.