I am not able to deactivate my subscription's renewal option—why is that?

As stated in your purchase confirmation e-mail, in order to deactivate the renewal option of your subscription, you have to do it at least 5 days before the actual renewal date. If you try to deactivate it within those 5 days prior renewal, the option will not be available to you.

If you purchased your subscription plan on your iTunes or Google Play account, please remember that you can only cancel it there as well.