Hey @jandaman12,
First, sign into your account at https://selfserve.publicmobile.ca and click on Plan and add-ons and then click through the lost/stolen phone tab to suspend your service. This will ensure no one can use call/text/data from your phone.
Next, send a private message to @CS_Agent and one of the mods will be able to help you with the blacklist.
Also, go to www.icloud.com and sign into your icloud account. Click on "Find my iPhone". Near the top center of the page, there is usually "All Devices" ... click it and select the iPhone from the dropdown menu. There is an option there to lock your device on the next page.
