I thought that MF memang liddat one? Meaning if it's kong, it's kong?
But surely you would know the telltale signs, i.e Hard to start, before it goes kong.

Anyway, most petrol station do stock  up on car battery, so you can go buy from there.
But the thing is, car batteries sold at petrol stations are of the common car models (so if battery type is the fancy one, hard to get).
& it fixed. So cannot nego. If buy from workshop can still nego, so will be cheaper IMHO.