Have some sympathy for the user
If was her first mobile phone and it was 2006, so not likely an early adopter of any tech. Purchasing tech from the likes of Aldi you are not going to get much support from the point of sale staff. The people selling her the third battery in six weeks were either dodgy or more than a bit thick.
I remember ~20 years ago observing an old duck† bringing her Braun electric toothbrush into the electrical retailer where she had purchased it a few years previously to have the (NiCd, I think) battery replaced and was upset to learn it wasn't replaceable. At the time I thought who is the silly one ? Her or the rest of the world ? I didn't think it was her.
† about my age now. :(