Failing to pay me out

I've been working for this company they unfairly dismissed me for beeing booked off sick by the doctor.. I brought all proof for why I was absent, their lawyer begged me to have a mutual separation with the company, told him I can't as this job was the only income I have that assists me to live, but however on a later stage they fired me. Upon engaging with the company I was promised commission which I worked super hard to achieve but have not been paid a cent for it, when I query it seeing that they dismissed me on the busiest time of the year (29 November) they keep tossing me from Manager to Hr to company owner. Now they have decided to all block me, I wish to at least go further my studies and do depend on the outstanding payment to give me a head start. I'm disappointed and now dont know what to do seeing that I trusted them and never even went to consult with the department of labour regarding the unfair dismissal that was a verdict to my case. Please advise and review