Unlocking sim carrier

I wanted to unlock my sim carrier as i am going abroad from my iphone 10XR . i called Apple yesterday afternoon and I'm sure they told me I could do this through my carrier 02. I did this from 'my 02' on my phone. Firstly I'm worried that my warranty is not valid with apple now and secondly I may have done this incorrectly anyway as on 'my 02' it only recognised my old phone iphone 7 so I then filled in the section of 'other device ' and put in iphone 10 XR and then gave my imei number which was actually incorrect looking back now. question is shall I start all over again with Itunes?

You can't.

Only the service provider can unlock it.

Clarification? Unlocking your device to use with another carrier should not affect your hardware warranty with Apple.