Hey there, kaan yılmaz
Please can you try and sign into your account here: https://account.microsoft.com/profile
Once you have entered your email address and password, you should be presented with the security challenge again to verify your sign-in request. When you see your old phone number listed, please click onto the option other ways to sign-in
This should allow you to choose another method to verify your sign-in request.
If you don't see this option, please can you upload an image showing what you can see, but please remove any personal identifiable information (PII) from the image. This will allow me to see what options you have available and what I can suggest next.
Hope this helps,
Nathan