I was not one of the three users (two moderators) who cast or processed flags on your answer.
However, as a moderator I can confirm that these actions happened, as you can see below:
- Ordinary user cast a spam flag
- Moderator 1 declined the spam flag
- Moderator 2 cast a spam flag (which deleted your answer, and presumably led to the 100 point deduction)
I can also see that you were contacted by the GIS moderators on 10 Oct 2015 about excessive self-promotion.
In this instance the question asked was:
how many (or which) zip codes map to more than one US state or US city?
Your answer appeared to be "here is how to use one zip code to find that particular zip code maps to two US states/cities". It therefore appears to answer a different and far simpler question, and acts largely as an advertisement for your API. Even disclosing your affiliation does not appear to have convinced two users (one a moderator) that your answer was not overt self-promotion.