Dear Ariana:

Using your word, toxic, your mother and grandmother are toxic. Your mother is toxic by using you to vent about her mother and in so doing dumping her distress on you and feeling relieved and calmer as a result, and your grandmother is doing the same when she calls you.

What each one of them is doing is using you so to relieve their tension and continue their dysfunctional relationship, getting distressed again and again, dump it on you and repeat.

“They don’t realize I’m not a child anymore”- they shouldn’t use you to rid their distress by dumping it on you now and shouldn’t have done it when you were a child, it is worse to do  it to a  child than it is to do  it to an adult.

“how can I set firm boundaries so this cycle won’t continue?”-

-don’t do what they do, dumping your distress on someone else, a third person not involved in a particular conflict. Instead resolve the conflict with the person involved.

Moving out is an excellent idea.

anita