I know of three telephone #s for "Freedompop":
800-228-9207
888-743-8107
855-703-5785
If you can't reach a representative at any of these #s (I very recently had success with 888-743-8107 and they helped me with my billing issue), GO TO FREEDOMPOP.COM AND LOG INTO YOUR ACCOUNT (hope you remember your password!).
THEN, CLICK ON (or, just hover over) "MY ACCOUNT" ATOP PAGE
From its drop-down list, THEN CHOOSE "ACCOUNT SETTINGS"
At the bottom of that page, you should see "DEACTIVATE ACCOUNT." (Click on it and follow subsequent instructions)

The phone number just our part of the "menu tree" and will not get you to a live person. Tried it several ways in the past few days. All I get is a salesperson who will sell you a program or another SIM card, but will not transfer you or offer any assistance if you have a problem.

I DON'T KNOW THEY WILL CHARGE YOU FOR SOMETHING IF YOU CONTACT THEM

CALL them.