This spoofed invalid number calls almost every day, despite being blocked. It is an invalid number because number prefixes cannot end with "11", like 911, 711, etc, so it is almost certainly a scammer making these calls.
As recommended by many here, I did not answer the call so I cannot say for certain who it was. I reported it, with the time of the call and what was shown on my caller ID so that others could see a pattern and amount of calls. As for spam, saying how I blocked it is hardly spam. Many others here mention all sorts of ways to block scam and spam calls. Do you call all of those "covert spam" as well?
Aaron Foss has made no secret of developing a commercial service, and this site has been pelted with rather off-topic sunny testimonials for that service since late 2013. That I think is the reason for the filter you had to defeat by munging its name. Admin has historically edited or removed many such posts which resembled yours. This time I guess they disagreed with my report, or we would not be having this exchange. No offense intended.
Agreed that there have been plenty of off-topic posts regarding said service. I'm just saying that I believe it is neither off topic nor spam simply by mentioning the method I use to defeat telepests. If Julia thinks it is, then she can search for all the times I (and anyone else) has referred to it in any form, and delete them.