Should I or shouldn't I?

I was let go from my boss last year after he said that I was not performing. He let me go without giving me any warnings. At first, I was quite down because I planned to resign before he could fire me but he made his move first. I guess, I was too late. He told me that my salary will be paid until 24th of December. He said they do not know how much they will pay me yet, but they will give me a call. I don't know how to calculate my salary but I can pretty much assume how much I will get. 


Two days after I was let go, my Mentor called and asked me to collect my first half of my salary. He said, the other half will be given at the end of January. I asked him how much I was supposed to get, he said he doesn't know. Again, I just assumed how much my other half of my salary will be, let just say more or less RM1k++.


January came to an end and I still did not get my other half salary. Just so you know, I am broke. Like totally broke and I have no job. So, after much discussion with my dearest and friends, I decided to ask my ex-colleague. She said she doesn't know when will the pay be. Maybe early of February. So I decided to wait till the end of first week of February. And then I asked her again and she said, she got her pay already. So I braved myself to SMS my Mentor and he said he will ask Elly on Monday. The boss' wife. 


Monday. I waited for his SMS but he just kept quiet. My other colleague who resigned a day after I was let go told me that he already got his other half. So I decided to SMS my Mentor again, and this time he did not reply. And suddenly, my ex-colleague told me that the salary has been banked in. I should get soon. The next day, I SMS my Mentor and he said that I should get it within 3 days. So I waited.


Today, I realised I have some money in my account. Only a couple of hundred ringgit. I refused to believe that that is my other half salary. I SMS my mom asking if she banked in some of her money for me and she said "NO". She checked it for me and she said it IS from my previous employer. I was shocked. How come I got so little? Where is the "guarantee money"? I asked my Mentor and he said he doesn't know. He said I have to take the payslip. Okay, to be honest, I don't want to go back to that company. I was let go without warning. I'm embarrassed. I decided to ask a few of the managers there and apparently, they have no idea either if I should get the "guarantee money" or not.


Now, one of the ex-employee who quit on the day I was let go, decided to go to the office labor (or was it labor office?). I found out that he and a few other ex-employees who had resigned or let go and some still working there want to make a complaint against the company. They want to sue if possible and they are asking me to join. Their reason for me is I was unfairly treated. I was let go without warning. That is against the policy. Come to think of it, some of my colleagues were given warnings and they resigned before my boss let them go. That is unfair right? I was told about 10 am I think, or was it 9 something? Okay I don't remember. I was told that that day was my last day but I still have to work until 5.30 pm. Stupid right? I mean, with no warning saying I will be let go if I did not perform by any specific date or week. 


Now I feel like joining them to make a complain. But, I'm not that kind of a person. Should I or shouldn't I?


p/s: I do wish that my boss will get what he deserves! He doesn't have the right to treat people unfairly and also cheated them off of their money. %$@!!