My CO biological mother and her name

So I decided to CO my biological mother a while back. (Long story short she is an evangelistic Christian and I am an agnostic/atheist and she was not willing to accept that - she has said some pretty heinous things like when my aunt was dying of stage 4 cancer and in her last few days of life that it was "too bad" she didn't believe in Jesus because she wouldn't go to heaven) oh and also this is not the woman who raised me. My biological mother left when I was a toddler and my step-mom is who I have actually called mom for the majority of my life and still do. My biological mom came back around when I was 16/17 and I called her mom since then as well.


Well I work for my sister and I asked her who would be taking my place for a couple weeks after I had the baby and she said our biological mother would. So of course I have to train her and teach her the computer software we use. Well I'm calling her by her real name since she is CO of my life and I'm only talking to her and anytime I do she gets angry and says "My name is mom." Then starts calling me daughter/darling and such.


I just don't know what to do. I had get number blocked on my phone but ever since I unblocked it to talk to her about work she's starting sending me all of her crazy religious texts non stop since I unblocked her. I'm only talking to her for business reasons and I mean literally, as I type this I am getting texts about how since I don't believe in Jesus I'm going to go to hell, the whole world believes in Jesus so there is no reason for me not to and blah blah blah...


I just really don't know what to do. I'm trying to stick to the CO and be firm but I have to talk to her for work. I just don't know how to handle her when she gets pissed off I'm calling her by her name. Like just right now she sent me a text saying "I am your mother and you will address me so."


Idk. At this point I'm babbling. I just don't know what to do... Any advice on how to handle any of this?

Edited for spelling