Banned for using AddOn

My account has been banned FOR CHEATING, I suppose because I used this AddOn: https://www.curseforge.com/wow/addons/cant-heal-you
All the AddOn does is whispering people if they are not in line of sight for a cast.

The ban is extremely unprofessional, because:

- There is no policy that forbids using this AddOn.
- There has been no notification to me that I would be not allowed to use that.
- There has been no communication with me after I have been banned. My request for support/clarification has been so far ignored.

Can any of the admins here make sure that there are guidlines that forbid using common AddOns? Also, I would be interested in how the decision process for making bans looks like within this interesting community.

You couldn't have been banned because of using that addon.