If you have a spacer that will allow a shimano cassette on a mavic freehub that you dont need any more how about selling it to a brother. I think it’s a 2mm spacer I have a 1mm spacer so if you have a 1mm to go with it that would also work.
The local Bike shop is no help at all. they told me to call mavic and mavic is out ot them.
Or if you have a link to some place that sells spacers let me have it.