Voice Mail Back Doors Closing?

Last year I got a phone call from a party who wanted all of the possible "Back Door" voice mail numbers, as if we were not showing all of them on our Back Door Voice Mail number list.  He mentioned a "bulk" use of these numbers.  I gave him nothing.  I realized he wanted to spam every number that was available through these Back Door numbers, and could easily do so with just the information on our web pages.  I found the method for this to happen and realized how it will go down. And go down it did.

Recently I was alerted that many of the remaining voice mail access numbers no longer offer the option, "To leave a message for another subscriber, enter their number." Fortunately, the function still works on some of the numbers regardless of the lack of the prompt. How long before the spammers cause the entire Back Door to close?

Related: New Verizon Voice Mail Numbers

Many of these numbers were used for callers to contact a mobile customer who was roaming outside their home area...what an ancient concept. As a result, the wireless companies have been slowly retiring these numbers, with a few disappearing every few months. Then we would receive the wrath from those customers wanting to know why their number was published on our site.

This explains how spam messages appear in your voice mail box without hearing the phone ring. It's another technical function now used for evil instead of for good. We will keep the numbers posted until they have been reassigned.