Same as jonesy, no idea about the battery problems (although in the past, I've seen that the battery failing was the first sign of the phone dying
), but another option is Belong:
https://www.belong.com.au/mobile/plans$10 / month, unlimited calls / text, 1GB data that rolls over every month & can be transferred to another Belong customer.
Runs of Telstra Retail, not Wholesale, network so no coverage out in the bush, but good coverage over something like 98% of the population.
Mrs & eldest son are happy with it, & I'll be dumping T (after ~30 years!!!
) & moving across myself as soon as I've chopped some credit down