Hello Don & Welcome to Just Answer,
Sorry to hear of any issue you are having with your calls being blocked.
To help you with this issue, may I ask:
1) The Make & Model Number of the phone system you are working with?
2) What phone service provider (phone company) you have for this phone line?
3) When that call comes in, do you have ANY indication that the call has been placed (and blocked), such as a "caller list" (or missed calls) in your phone?
I see it has been a few days and I just wanted to follow up to see if you have any more questions concerning this issue or if the issue was resolved?
I look forward to any further questions or results that you may have.
Thanks, ***** *****--. .-(im)