Mattermost (dot com) is a great open source alternative to Slack.

++Mattermost

Slack closed my accounts and deleted my data I am Iranian but I am currently lawfully residing in us on student visa so I don't believe there's any excuse for this Behavior

The best way is just keep asking for answers. There are so many Iranians working in software companies. They can't just simply wipe out accounts just because

I wonder how they knew you were Iranian.

It may be asinine, but in no way, shape, or form is this racism. Just stop.

Agreed. Appalled that someone down-voted the comment. You can't just shout "racism" and make it so. As outlined in the screenshots - the countries that Slack claims are sanctioned vary greatly, as do the races which occupy them.