There are a lot of “Catholic” nuns out there who are not really Catholic. They don’t leave the church because they have comfortable lifestyles living in thier religious communities. Some orders are not dependent on the local bishop. The communities that they belong to own thier own property. Also many of them collect salaries from non profit corporations that get gubmint fundin. Not all nuns are like Mother Theresa.
Not all sisters are nuns. In addition, there's no "h" in Teresa. Two different women.