Iphone 12 pro max ringing on silent...

Happens once in the morning? I read previous posts and none of them apply. These are callers like spam and unknown that are ringing through and it's only in the morning it seems (maybe the first phone call of the day?). I recently had an update from T-mobile that was allowing visual voice mail all of a sudden which they were able to deactivate and this issue started the within the next couple of days. They said there was nothing they could do and suggested I turn my ringer to silent (which it always is, except when I'm working delivery)...