Make sure you're in bizarre fancy dress costume every time they see you now as a start point, then the afformentioned Satanism!
I live in an apartment where I have listened this from both neighboring apartments!
Dear Barb and Tom, eat shit! I doubt anything we're doing will screw up her brain half as much as you taking her to church! Have a nice afternoon, your Pagan Neighbors!
Send a polite note back inviting them to the orgy and Black Mass....
The statue of Baphomet goes up this afternoon! And activities around it commence soon after........