1. https://www.telus.com/en/bc/support/article/disable-lost-stolen-phones
2. https://www.telus.com/en/bc/support/article/replace-change-mobile
If the phone was on contract and it has not been paid off yet, you would still be responsible for the rest of the balance owing. When replacing the phone you would have two options. Buy a phone yourself separate from Telus, or get another through Telus.
If you find a post useful, please give the author a "Kudo" or mark as an accepted solution if it solves your trouble. 🙂
