If you are using Authorize.net with ReCharge, verify that all transactions have been approved in Authorize.net before shipping the order.
We got orders in processed by ReCharge and marked as paid but when we checked with Authorize.net, the transactions were actually declined. It looks like a bug in ReCharge that allows an order to go through after a customer attempts to place a subscription order successively (6 to 7 declined attempts with multiple cards within 20 seconds of each other). On the 6th or 7th attempt, the ReCharge app processes the order like the transaction was approved in Authorize.net even though it was not.
We've had the same issue and have reached out to Recharge support but they always default back to Authorize saying it must be an issue on their end when it clearly isn't, as they have declined the charge. Has this issue persisted for you? We've also had a nearly opposite issue where cards will be perfectly working on Authorize but then they are reading "INVALID" on Recharge yet if you cancel the subscription and use the same card to start a new one, it will go through. Again, Recharge is saying this is an issue on the Authorize side even though it doesn't really feel that way.