Mouse not charging past 1 percent

Ok, I understand. Looks like the internal rechargeable battery is spent or, possibly, defective. I suggest that you give Apple Support a call to see if they have any options other than getting a replacement.

To contact them, just select the "Support" link on the lower left-hand side of this forum's web page.

What are you using to charge this mouse? An Apple power adapter?

Did you try another charging cable?

Have you tried resetting it? Ref: https://www.technewstoday.com/how-to-reset-magic-mouse/

It would help if you, at least, provide us with the make & model of this mouse, how long have you had it, was this an issue before, and what have you tried, so far yourself, to resolve this?