that's the same, they have no warranty. One could block the card just after having received the software. And companies could not prevent that from happening. Usually isntallment payments (at least here) are made on the basis of a contract, that says that in case of missing payment, the object will have to be returned in the original condition. You understand that with software, this does not give any warranty. As I said, one could copy it, store the copy then block payments and return the original.