I have a problem with an insulting comment on a post which I flagged two times as offensive and not constructive, but the moderators did not delete it.
What is the next level where I can report my complaint?
I have a problem with an insulting comment on a post which I flagged two times as offensive and not constructive, but the moderators did not delete it.
What is the next level where I can report my complaint?
There is a contact us link at the bottom of every page that will allow you to contact SE directly. Moderators do not have access to messages sent this way, although SE staff may reveal certain details if/when they follow up with us.
I have doubts that they will involve themselves too much in the moderation of comments, but I have been wrong before. On the other hand, if enough regular users flag a comment (the threshold appears to be $3 + \lfloor \frac {\mathrm {score}} 3 \rfloor$, with possible reductions due to content) it will be deleted.
I will just echo what Arthur said. I have flagged content before and have had the flags rejected. I have then contacted SE directly and every time I did I had the content removed. From personal experience, I would say that this is a good way to go.
Note, if your complaint is also rejected from the higher-ups, then I simply just wouldn't worry about it. I don't think that there is a need to contact SE everytime the moderators don't come down on your side. Often I think it is better to just let it go.
If you want to try something between flagging and contacting SE directly, then you can try to catch a moderator in chat. Here you might get a nicer response and you might be able to hear their side.