Somewhere in the mailbox that receives your phone bills, there is probably a notice you have not read. Three Telstra business voice products are being wound down: Calling for Office 365 is reported to be withdrawn at the end of November 2026, DOT in August 2027, and Business SIP has been closed to new customers since May 2025 with no published end date at all. If you are on one of them, nothing breaks this week. But your service is almost certainly frozen, which means you cannot add a user or a feature at the moment you most need to, and the migration gets more expensive the longer you leave it. Here is how to find out which product you are on, what the freeze is already costing you, and how to move calmly.