More than 90 staff have returned to work; however a handful still have to go through the disciplinary process.
Derry’s Trades Union Council is urging anyone who needs help to contact them.
More than 400 Firstsource staff have expressed an interest in joining a union.
One of those told us: “If it means being able to go to the toilet when you want to, it will be worth it.”
There are several disputes inside Firstsource.
The main one involves how SKY customers had been dealt with; staff insisting they were following instructions.
However there are several wider issues in how staff are treated generally within the company.