No, you only pay the subscription fee.
You get 30 days grace period for the monthly pack and 7 days grace period for the weekly pack to renew and keep your pack active. Once the required balance is available, the pack will be renewed automatically, and if the grace period expires, you’ll have to re-subscribe to the offer again.
Yes, your subscription will auto-renew unless you deactivate it.
No. All unused minutes will expire at the end of the validity of your pack.