iphone – How to stop FaceTime and iMessage alert

I have a data only sim which has poor signal at home. Every time my phone loses signal and gets signal again it displays this message.

Der vom Netzbetreiber gefallene SMS-Schaden beim Aktivieren von
FaceTime und iMessage

Which means it could not sent an sms to verify the number for FaceTime and iMessage.

If I leave my phone for a long time it connects to the network maybe 30 times then I have 30 alerts to dismiss before I can use my phone.

I really don’t want to change my number as I’m only using a data only sim while in another country.