There will be an update to the subscriptions plugin soon that addresses this.
It will also resolve the tax issues: Automatic_tax.enabled for Discourse Subscription plugin
and enable other payment methods. How can I customise the discourse-subscription plugin?
Please reach out if there are any other pain points you have with this plugin. I think I am aware of most, but there are still some parts that I would like to know more about. For example I would like to learn more about your perception of the campaign feature. Is there someone here who has used it? 