Current message going to old phone

You need to change/add the number on your Apple ID. Look in the Security section when signed in online. You may have to add the new number before you can remove the old number. After the change, allow up to 24 hours for the change to sync. Before trying to make the change, sign out of Messages/FaceTime on all devices/computers.

Apple ID - Manage  

marguerite299 wrote:

My mother has and has been going through my messages and even sharing with others.

You gave her the phone as is, without wiping it first? This is what you'll need to do with the phone What to do before you sell, give away, or trade in your iPhone, iPad, or iPod touch - Apple Support

marguerite299 wrote:

I have a new iPhone with a new number through a new provider. My messages appeared on my old iPhone. I then removed the old iphone from my known devices, signed out of all devices signed in with my Apple ID and changed my password but the messages are still appearing on the old iPhone. I do not have access to the old iPhone so I need a way to stop this from happening without having the iPhone. Please help!!!!

How do you know it is going to your old phone if you don't physically have it?

Where is your old phone?