New phone same sim same provider but my number has changed

[IOSNightmare]

I need my old number back. New phone same sim different number even though in my phone settings it still shows as my old number if I call someone it's different though 

[PandJ2020]

Can you explain what you've done?

If you've activated a new SIM then it will have a new number.  Did you order a new data plan?

If you simply moved the SIM from your old phone to new phone then it can only have your existing number.