I cant get 3g or 4g connections

[thefinn]

i did an upgrade to my iphone and can no longer get 3g or 4g and therefore no internet

[gmarkj]

When you say an upgrade, do you mean you signed a new deal @thefinn ?
If yes, then unless you ticked the box to keep your sim you will be getting a new one in the post and it will have your connection live on it instead of your existing one.

Get in touch with customer services to see if they can get the old one live again, otherwise you will need to wait until the new one arrives...

Call 202 or 0344 809 0202, or message on social media:

Facebook (https://o2uk.co/O2CFB) , Twitter (https://o2uk.co/O2CTW) or Instagram (https://o2uk.co/O2CIG) 

[thefinn]

Not a phone upgrade and apple IoS upgrade - I have spoken to apple, reset network settings etc and apple now say it is a carrier issue

[thefinn]

I have 2 iphones on same package and other works fine, so not reception, coverage issue. I can still receive calls and sms but not 3g or 4g

[gmarkj]

Have you tried swapping the sims round to see if they work in the other phone @thefinn ?
Other than checking the APN is still correct I can't see any other reason why it would not work.

https://community.o2.co.uk/t5/Apple/Connecting-iPhone-to-Data-Services/m-p/544210#U544210 

So maybe a replacement sim is required?