Need urgent help

I have worked for Milpark Radiology incorporated for 2years 11 months, resigned with immediate effect due to intolerable working conditions and disrespect from the Practice Manager and his assistant, now they don't want to pay what's due to me and they do not want to send my claim to the forms to Liberty for my provident fund, I have never experienced such in my whole working life, I need someone to please help me get what's due to me.