@Olivia1
If you are not in a 5g area, check that 5g is not enabled in your network settings.
Also check for any faults here O2 Service Status
and some help here Guide: How can I sort out my network issues?
I have no affiliation whatsoever with O2 or any subsidiary companies. Comments posted are entirely of my own opinion.
This is not Customer Service so we are unable to help with account specific issues.Currently using:
Pixel 7a (O2 & Lyca), One Plus 6 (Sfr), iPhone 12 Pro Max (Vodafone)