I can't note all the failed calls.
Nobody is suggesting this. But you do need to note a single failed call, and a single working call to provide enough information to troubleshoot.
JetA1: Again, any call made directly to or from my number works perfectly.
Can you answer whether that includes from the specific Vodafone number used for the business. What happens when you call your Skinny phone, from that specific Vodafone phone?