Return a previously purchased non-renewable subscription, not the current one. Possible?

I am using an iOS application with a non-renewing subscription. Not much relevant information was available on the Internet; therefore I am looking for your guidance.

Most often, I am concerned about the case when a user bought a subscription once, and then immediately after the purchase in order to extend the service life (see such a scenario here ). What if this user had to return the first purchase, leaving the second intact? Is this possible in practice, or am I too paranoid?

Assuming the above case is possible, my application will run into a problem because, as far as I know, it verifyReceiptreturns only the latest, good receipt (see Managing Subscriptions with In-App PurchaseWWDC'12).

I have not found anywhere that Apple provides relevant information on the refund policy.

(An auto-renewed subscription seems to rule out this case, since iTunes automatically updates and it seems impossible to renew this type of subscription until iTunes allows it.)