Rights

I wrote for a newspaper on a weekly basis for over 13 years, with deadlines for early weekly submission of the material (I have the emails saved), and I received a payslip under the heading 'authors' fees'. No contributions whatsoever were made. The salary was never raised due to seniority. When I resigned, I did not receive any severance pay whatsoever (the departure was due to the editorial board's refusal to raise my salary, and obtaining a much fairer-paying job at another workplace). I wanted to ask: What rights, if any, do I have, how can you help in this matter, and how much is this expected to cost. Many thanks in advance!!