u/Ok-Drawing-9929

1 (19 ftm) came out to my grandma as trans and bisexual about almost 3 years ago. I've known ever since I was a little kid that I was never meant to be a girl. When I came out at 16, her response was accepting as far as I remember.
I was out of state last week visiting other family members and during my trip, my triend (16 nb) (we'll call them Alex) and I were texting each other about school and their mom who was in the hospital. Out of nowhere, they changed the topic by talking about how my grandma is transphobic and I asked them what they mean. They said that at Christmas time, she (my grandma) told them (Alex) that being transgender is a disease while using my deadname and that my grandma and their grandma have talked shit to each other about trans people in general (my grandma has been best triends with Alex's grandma since they were kids, so Alex and I are family friends). One of the other things Alex said that my grandma said other than her thinking it's a disease, is that I'm still a girl because I don't have a penis. I kept asking Alex if they were completely sure that she said those things. Not that I didn't believe Alex, but I wanted to make sure of it multiple times. I was hurt, but I tried to not let it ruin the rest of my vacation.

Yesterday, my mom and I called my grandma on my phone to wish her a happy Mother's Day. My grandpa picked up and asked "Why are you calling on deadname's phone?" My mom kindly corrected him on my name. He apologized and said that my grandma still has me as my deadname on her phone, so I feel like that confirms the transphobia. I am going to set up a time to talk with her about it face to face. I really don't want to cut her off because I love her and my grandpa and I would feel bad about not seeing my grandpa because they're around each other all day every day because my grandpa has health issues both mentally and physically, but I also don't want to be around someone who won't come around to accept me, so I don't know what to do on that part. It just hurts me that she would pretend to be supportive of me and talk shit about me to Alex and their grandma, which is extremely fucking childish. Any advice would be greatly appreciated and I will post any updates.