My mother takes care of niece whom my sister abandoned. She calls me every day complaining, but I don't want to hear it anymore.
How can I avoid family members who stress me out?
Set firm boundaries. Either you can say she can complain for X number of minutes and no more, you change the subject or let her go to voicemail, she can leave as many as she wants and you dont have to listen, you can delete them. The boundary could be that you do not hear her complaining at all. Boundaries are hard to set harder to enforce but worth the effort of setting them and sticking by them! This video on Boundaries could be beneficial.