Re: can't make any call
I doubt reloading the OS is needed. But who knows. If were me, I would hold off until I tried other things less time consuming.
Regarding the SIM, I would try your SIM in another device *and* try a known good SIM in your device.
If you do reload the OS, be sure and test before you do anything else. But if you haven't ruled out the SIM, or have a known good SIM to test with, then you have no way of knowing if the OS reload fixed anything or not if it still doesn't work.