If you want to prevent your further Cash app transaction, then you should have to report your Cash Card as stolen or lost via the Cash app. To do this, you have to click on the Cash Card tab from the dashboard. Now, move further to click on the image of your Cash Card. Afterword, go to click on the problem with the card section. If you get any issue there, then take Cash app help.

https://www.onlinedigihub.com/payment/cash-app-customer-service