Help Phone services - No data service

[hstroph]

The phone is wifi-connected for data service, and is collecting email and streaming a radio station. There is 0 or 1 bar of cellular service, which is normal for this location over the past 6 years

Recently, every 30 seconds or so, the phone gets a notification with audio alert:

Phone services
No data service
Temporarily not offered by the
mobile network at your location

Is there a way to disable this annoying notification please?

 

[MoodyBlues]

Have you tried long-pressing on the notification when one pops up? That should bring up some settings for the alert source, which you can modify.

 

[ocnbrze]

Why not just put the phone into airplane mode? That should take care of those notifications and you will still be able to connect to wifi.

 

[hstroph]

In "Developer options", I disabled "Aggressive Wi-Fi to mobile handover" which seems to have solved the problem ... not sure how that ever got enabled.

Thanks for the suggestions.

[EDIT]
Well, no such luck ... the notifications stopped for a while but are now back again.
[/EDIT]
Long-pressing the notification states "Notifications from this app can't be turned off." Not sure how to proceed. I need notification sounds for such things as email and text messages, but this one every 20 seconds or so is just too annoying. I'd welcome any other suggestions, please.

Airplane mode is not an option, as I need to both make and receive the occasional phone call despite the poor service.