login to your self serve account and click on "change sim" make sure the last 4 digits match the sim card in your phone. if it doesn't match then someone is commiting fraud.
contact customer support mods
click on the question mark chat bubble to the bottom right of your screen
type "security or identity fraud issue" or "no service"
(use the chat bubble options, then click "submit a ticket, click me" option)
*login using your community account
make sure to check your inbox(top right corner envelope icon) periodically, for a response
