Bose Soundlink Max - Batteria

I own a Soundlink Max, from an audio point of view nothing to say, it sounds really good, the point is that I'm deciding whether to keep it or return it, in view of a future battery change, as I would like to keep it for several years. There are no spare parts available on the internet, I called Bose assistance and they told me that there is no spare part and that it would need to be sent for assistance, but they couldn't tell me how much it would cost to change the battery! Absurd! I'm seriously thinking about moving on to something else! It's absurd to own €400 of this type of product and not have decent assistance!