Try waynemazda.com (best price w/o S&H) or mazdaparts.org (free S&H >$100).
If you are sure the assembly is broken, replacing it should not be complicated.
Remove the door trim (unscrew a couple screws, and pull the trim toward you starting from bottom edge)
is easy. You should see what to do after the trim is removed.
Make sure you raise the window glass first.
Send me a PM with an e-mail address.
I will send you a couple pages from WorkShop manual if you really worry about the trim removal process.