SK going back to moms and reporting info

How do we stop SK from going back to HCBM and reporting all happenings at our house? Does anyone else deal with this? Nearly every week H gets an email of what SK has told her. And while none of these things are even matter, she copies her lawyer on each of these emails. We are trying very hard to distance ourselves from her constant harassment but the crux of the issue is the older SK is always reporting back. And she hates us. Hates H, hates me, hates our kids. It just feels so violating and it’s to the point when SK (that’s reports back) is at our home, he is not someone anyone wants to talk with or hang out with much as we never know what will get reported back and twisted.