We use the standard Shopify trial system that is not prepared to deal with trial extensions and we consider that our trial period gives stores enough time to test the app capabilities and see if the app is a good fit for their store. So we are sorry to say that there's no easy way to extend your trial.
When you install our app for the first time, you can use it free in a period of time (the trial period). The trial period only available once for each store because if the trial period were available every time the app is installed, a store could uninstall and reinstall the app many times to use the app for free forever.
Our Delivery Date app has a trial period of 14 days. You can re-install the app as many times as you want within those 14 days and you will not be charged.
If you don't want to be charged when the trial period expires, you have to uninstall the app before that date. But if you uninstall the app and install it again after the trial period, you will still be charged immediately.
Unfortunately, yes. When you uninstall the app, your monthly subscription will be cancelled. Thus, Shopify will ask you to accept the recurring charge that is associated with the app subscription again. This happens even if you uninstalled the app one minute ago because your recurring charge is cancelled.
Please note that payments are managed directly by Shopify. It is Shopify, not us, who charges you, and then transfers our part to us.