I don't want pandora and I didn't do it someone had my phone it's blocking me from upgrading my storage

If you've subscribed to something and no longer want it cancel its auto-renewal : View, change, or cancel your subscriptions - Apple Support

If you currently owe iTunes money for the previous payment you may not be able to cancel it until you've paid it. If you let somebody use your phone try contacting iTunes Support and see what they say e.g. via your purchase history, the emailed receipt, or the top right of every page on here