How to join 7-11 mafia in game:

Search for Visiphone in game lobby (purple PC interfaces around some corners)
Use it
Arks Search
Team Search
"7-Eleven Mafia"
Send Whisper to team master.

Hopefully FerdhatEpochsis is online to take you.

IF HE IS NOT ONLINE.

Arks Search
Player Search
search for "FerdhatEpochsis"
Add to friends.

Hopefully he will add you to the team when he gets online.
Alternatively also search for Player "Space Vexx" from Visiphone and add him as well. These men, they fight for your freedoms.