First, go to the payment gateway you used to pay for the subscription. The links below will take you to FAQs with detailed instructions for how to cancel in each gateway:
– How do I Cancel my Subscription in Google Play?
– How do I Cancel my Apple App Store Subscription?
– How do I Cancel my Subscription in PayPal?
– How do I Cancel my Subscription in PayPro Global?
Inside each gateway, the cancellation will take effect at the end of the current period.
If you experience any problems, contact the SimDif team via the Help center in the app. Look for the '?' icon in the bottom left corner, and go to the 'Assistance' tab.