I actually have 2 2d sims that are not in a cellphone.

One in a portable hotspot, the other in my home alarm system.

I dont have to worry about the hotspot one, it's linked to my mobile and seems to look after itself.

The alarm one though periodically needs intervention, and it's against the security company's rules to open their box to get that sim out.

I've just had a difficult day finding out why the alarm sim stopped sending txts a few days ago.

Turns out its $10 top-up plan (topped up automagically by my cc, and last topped up Aug 13) doesnt exist anymore (it stopped in Aug), and it was moved onto a casual $13 plan, whereupon it seems to have very rapidly run out of credit.

Messages were sent to that sim about the plan dying, and about the credit running out, but of course I never saw them.

A lovely person at 2d who has now put that sim onto a monthly $8 plan informs me there is no way no how I can get messages sent to that sim redirected to a place where I can view them.

Do all non-phone sims have this issue?