Bissell Bolt Battery Replacement Anyone?

It appears that the Bissell Bolt ION 2 in 1 vacuum is a great example of planned obsolescence. I’ve had two of them and you are lucky if the battery lasts the two years while in warranty. Bissell does NOT sell a replacement battery and I have been unable to locate an after market replacement.. Wiring some odd batteries together is the only suggestion I’ve seen. Anyone have an idea about this?