You deleted a product or a variant in Shopify, or replaced it with a new one, and some subscriptions still include the old one. This article explains what happens to those subscriptions and how to fix them.
What happens
Deleting a product or variant in Shopify does not change the subscriptions that include it. The line stays on each subscription with the name and price it had, but it no longer points to a product in your store.
The subscription keeps billing that line at its price on the subscription.
Stock checks cannot be relied on for that line. With Attempt only if inventory is available, Shopify has no stock left to check for it, so an order can still be billed for it even when you have nothing to ship. Attempt partial delivery (Beta) may leave it out of an order, but not every time.
Replace it on one subscription
Open Contracts in your Subi admin and open the subscription.
On the Next order details card, click Edit. The Product details window opens.
Click Select products and tick what the subscriber should get now. For a product with several variants, tick only the one variant you want: ticking the product itself adds every variant. Click Update. The product is added to the subscription straight away, at quantity 1. It gets your subscription plan's discount when a plan covers it at this subscription's delivery frequency, otherwise its full price. You can check and change the quantity and discount in Product details.
In Product details, click the bin icon (Remove product from subscription) on the old line, then click Save.
Add the new product first: Subi does not let you remove the only product in a subscription.
Before you delete a product next time
If your plan includes bulk actions (the Subi and Subi Plus plans, or the Bulk actions manager add-on), move its subscribers first, while the product still exists: on the Contracts list, select the Subscribe & save subscriptions, then Bulk actions > Swap product, and pick the product to swap and the new product. The new product must still be in your store. Subscriptions whose discount cannot be carried over are not swapped and are listed in the results file: replace those one by one before you delete the product. On other plans, replace the product on each subscription as described above before you delete it.