iphone 7 - No mobile Data or calls randomly

[#1]

Hi, 

Hope you can help, im on the latest ios 12.4 and oive the last couple of days im constantly losing my service on my iPhone.

I get a message : 

"Your mobile phone cannot make or receive calls or access mobile data until it has been updated" 

And then

"Mobile Data Update Failed"

Is there a carrier update to fix this. I reset the phone and it fixes it for a short time then happens again. I've reset network settings and re installed IoS and its still happening.

Also logging with Apple but wonder if anyone had this error?

Thanks

Mike

[#2]

I quick google seems to indicate it's a known issue with some iPhones https://www.payetteforward.com/iphone-cellular-update-failed-heres-why-fix/

[#3]

Thanks MisterW, I've tried all them and failed.

Apple have acknowledged the problem :

https://support.apple.com/iphone-7-no-service

But my model isn't listed as its the A1778. Apple have just quoted me £360 for a repair for a hardware fault! The phone is only 2 years old. Not sure what i can do now, surely a phones hardware shouldn't be failing after 2 years.