SIM stuck on a different phone

[Lisa156]

I transferred my number to a new iphone however the new iphone was defective so I cleared the data and returned it to the vendor.

However, when I tried to revert back to my old phone, the SIM was not working.  The SIM appears to be allocated to the defective new phone despite it being cleared of data.

How do I reactivate my number/SIM on my old iphone?  At the moment I have no ability to make calls. 

[bristolian]

To avoid doubt, are you talking about an eSIM? With a pSIM you simply insert it into the phone you want to use it with

You may need to contact EE-CS from another phone - 07953 966150

[Lisa156]

Thanks.  It is a physical SIM.  However, it was removed from the defective iphone and returned to the old iphone but still does not work.  Is it possible that I unintentionally generated an eSIM?

[Matt_124]

Very possible, almost definitely.

The iPhone Quick Setup process gives an option to "transfer your number" to your new iPhone.

This options gives you the choice to proceed or set this up later - most people inevitably think this is something they want to do and when agreeing this performs an eSIM conversion and deactivates the physical SIM.

[bristolian]

If you followed any prompts for "setting up eSIM" or "convert to eSIM", that's a possibility. Did you?

What, if any, error messages do you get when inserting the pSIM into either phone?