Ah! I'm now thinking that they just told me that it was my fault that the battery was flat and, in actual fact, the battery was faulty - hence them giving me a brand new one at no charge.
Makes sense!
I have owned a ZS EV for over 3 years.
No problems except when I failed to sign out of the app and the 12v battery went flat. An MG mechanic came to the house and installed a new battery - no charge. I thought this was very odd, but great.