Calls going directly to voicemail within hospital

I am a physician and take calls within a hospital. About 3 weeks ago my phone stopped receiving calls from hospital phones. I surveyed the literature on the internet and on this forum and have checked and triple-checked all the recommendations. I called my service provider and we went through their checklist and all of them were turned up as not the cause however they were pretty much what I have seen from Apple. We ended up creating an eSim and I thought this may have helped however it is not sustained or never really solved the problem. It created a different, unrelated problem which is another story.The calls are not frequent enough to know if it was fixed or not. however at this time when I pick up the hospital phone and dial my number it goes directly to voicemail. I checked everything and even toggled the suspect areas to make sure, including the silence of unknown callers, and reset my provider carrier settings . It created a different, unrelated problem which is another story. I am thinking of resetting my phone as it worked before. However, it would be nice to know what causes this "malfunction". Thoughts?