Household (3 phones) can't make or receive calls

Hi.  We have 2 samsungs and 1 iphone in the house and today we can't make or receive calls.  Texts work (in and out).  The mobile signal is very poor here so we always use wifi calling and until today, that has worked fine.  I've tried the old reboot method to no avail.  I also know I have 3 voicemails - I just can't access them and I'm getting a bit frustrated.  This seems to be the only place I can register the issue - is there any other way to speak to smarty?  I also tried the airplane mode on then off and that hasn't helped.  Can anyone help or do I have to switch us all to a more expensive network?

Thanks!