Subscribing to myCloud Pro will start off a subscription that is valid for 30 days, which after this time will be automatically renewed at the end of each billing period. If you have selected payment via Swisscom invoice, the amount will be debited from your next Swisscom invoice. If you pay by credit card, it will be charged again.
If you have activated myCloud Pro with the Smartphone Comfort Package (no longer available), the myCloud Pro subscription will be valid as long as you have subscribed to the Smartphone Comfort Package.