New IPhone 16 Old Sim can’t send or receive calls

[Scotts1992]

Purchased new iPhone 16 pro and put in my old SIM card from iPhone 13 but I can’t send or receive phone calls now. Texts, FaceTime, WhatsApp etc all work but when I try call a number it says “number you have called doesn’t exist”. Double checked all the settings etc that it mentions online but nothing worked. Any help would be appreciated. Ps on a monthly sim only deal 

[Chris_B]

@Scotts1992  If you go to Settings/apps/phone does your number show correctly? 

[bristolian]

Does the SIM still work in your old phone?

What are the settings that you've found online?

[Scotts1992]

Yeah number shows up correctly 

[Schockwave]

@Scotts1992 where did you purchase the phone from?

[Scotts1992]

Yeah still works on old phone

ive made sure call forwarding is off, reset phone, turns data off and on etc 

[Scotts1992]

Purchased from Argos (paid phone outright) and now using my sim only monthly plan with EE 

[Scotts1992]

Update this morning, phone still saying no service but when calling the phone it's going straight to voicemail rather than saying number doesn't exist. I've removed and reinserted SIM but still no service. Checked location services and reset network settings but hasn't worked 

[Schockwave]

@Scotts1992  Have you tried putting someone else’s SIM card in your new IPhone to see if that works? Otherwise I would take it back to Argos, as there may be a problem with the phone, also it should not be locked, but go to settings, click on general, settings and see if it is locked to a network.