Yes of course.
World Economics has teamed up with PayPal as it's payment provider which means you can mange your own billing within the PayPal interface at any time. You can stop or pause payments whenever you wish.
You remain in total control of your billing without having to even contact World Economics.
If you cancel your monthly payments, your account will be disabled when your next payment is due. If you have paid annually, then you will not be automatically renwed on it's aniversary. We can not offer refunds on annual payments though.