Bio mom says I can't discipline the kids

My daughter Andrea is 16 and my son Matty is 14. They're technically my step kids but I don't call them that. They're my kids. There bio mom has been back in their life for a month. She called my husband's phone and I answered. She was asking why she couldn't get ahold of Andrea. I told her that Andrea is grounded because she got mad and hit Matty in the eye so I took her phone away. She says I have no right to take discipline her children. Only their dad and her as their real mother can. Bitch hold tf up. This bitch abandoned her kids when Andrea was 20 months and Matty was 3 months. They don't even remember her. She just now came back. Who took over when she was gone? Me! I changed Matty's shitty ass diapers. I potty trained both of them. I tucked them in bed, read them stories. I carry an EpiPen on me because I know Andrea is allergic to oranges. I know Matty has a bedwetting issue. I changed every sheet. If he was a sleepover I hid his pull up in a sleeping bag so he could put it on in secret. I was there for Andrea's first period! I picked her up from school if she was cramping too much. I stayed with Matty if he had a bad dream until he fell asleep. I WAS THERE! SHE WASN'T! I hung up in that bitches face!