Signia Rechargeable Batteries

I had mine replaced for free near the end of the three year warranty. they should be good for another three years. after that I have to pay for new batteries. But here’s the deal: I’m sure I got entirely new aids at the the three year replacement. My audi said this is typical.. It’s cheaper for Signia or any brand to simply give out new aids than replace the batteries. Good for me! After six years, I don’t know what will happen. I may want a newer model aid by then. But the cost of replacing Signia batteries will have been less than what I spent on replaceable batteries for six years, with a lot less hassle. So I’m good with rechargeable batteries.

I got my Signias off eBay so I am trying to find a friendly clinic to help me with the warranty.
Alternatively, has anyone dismantled a Charge and Go and replaced the battery themselves?