Your subscription UX needs serious improvement. The potential flaw I uncovered is as follows.
Once you create a new subscription entity, it immediately takes into effect. Customer credit card gets charged immediately prior to shipment (legal issues here). And fulfillment of the subscription gets queued and cannot be overridden. For instance, I made a subscription that I intended to be for 48 bottles, but instead I carelessly chose the 12 bottles and clicked add subscription. The subscription goes into effect, but the UI allows you to change your subscription information. However, changing your subscription does not override the current fulfillment, which is very absurd. What if I made a mistake with the shipping address instead? When I change it then it is pointless as your system would not take into account the change.
If such feature is complicated to build, then perhaps provide a phone number so that we can call an agent to tell your plant/warehouse to update the fulfillment… An email is not a great customer service, period.
Please take this seriously as not supporting this feature is absurd in today’s standards.