Video doorbell keeps going dead after install without a chime box

I see lots of previous posts about a video doorbell going black after install without a chime box.  I am having the same issue and have gone through 3 doorbells.  The "technician experts" from xfinity keep saying its electrical.  I have replaced the transformer, same results.  I am having an electrician out today to look at the overall power.  I think this is not the issue.  I think there is an issue with the circuit when you don't have a chime box.  If this is a known issue why won't xfinity simply say so.  This has been going on for months at my home and I am ready to dump the door bell and the entire xfinity home system.  Should I simply wire the unit with the chime circuit as if I had a chime box?  Does anyone have an answer?