Swapped from ee to 02 using a pac code. Everything changed over but still unable to receive messages from some numbers but can take calls. Their messages seem to go to old sim.
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)
It sounds like a part port out by EE (routing for sms is not completed), if you contact o2 Customer Services, they should be able to raise this with EE and get them to complete the port out.