I originally downloaded Tennorshare Reiboot in the hope that it would repair a couple of faults that had developed in my old iPhone after a software update.
At first I was frustrated because it appeared that the software was unusable without a minimum of a 1 month subscription. However, the company generously offered to send a 1 month registration code free of charge in exchange for a 5 star review. Now I consider that to be great customer service.