iPhone 6 phone number change

I recently got a new number and have a working T-Mobile account. I can send and receive messages and calls. Except for my old number (which is now being used by one of my family members) whenever I click on her contact and send a message, the message name shows up as me. But when I go to my contact it shows my number. For some reason In messages it is showing my old number is me but everywhere else it is correct. I have checked iCloud and messages and calls in settings and they are all set to my new number. It’s only when I message my old number it says: Me

thanks