calls going to old android phone

This is because your active cellular service SIM card is still in your Android phone. If this is the case the remove the working SIM card from your old phone and install it in your new iPhone. This will transfer the service to your new iPhone. If you have already moved the SIM card or have an active SIM card in your new iPhone then contact your carrier for further help.

Axel F.

We don’t know what “transferred everything” means. Clearly you did not transfer everything because if you did, this would not happen.

Perhaps you did not use the same SIM card, for example, which would be perfectly OK as long as your cellular carrier knows what you did and approved it.