manjaro-phosh did make calls -- now nothing

[Dragonborn]

The sim connection icon  is shown on the PPP front page at the top along with wireless, etc  I think there is connectivity but how good is not known.

Hardware issues could be the modem itself or the sim card holder as you suggested.  I have also suspected sim holder as a culprit which is addresssed by me in another thread.

tom kosvic

If you have the sim icon, then I assume that the modem itself *should* be okay.
If you can try to get a good picture of your sim and sd slot, you might be able to zoom in and see the pins better to check for broken contacts. 
Otherwise, we might want to find commands to run to check your modem status when the sim is inserted.