(1) Open Tian Tian Fund APP, or log in to Tian Tian Fund official website and enter "My-Account Management-Bank Card".
(2) Click "Add New Bank Card"
(3) You can see that "only the savings card in my name is supported", so even if he has your mobile phone, he can't withdraw it as long as he doesn't have your ID card, so don't worry too much.
-Original answer, hope to adopt-