Edcon does not pay what is due when you leave

I resigned from edcon over 5 years ago, i was paid incorrect salary and i still have not received my pension payout. They contacted me 3 years ago and got my new banking details and also asked me to forward forms to them via an edgars store, which i duly did. The hr department on my resignation said they would pay me the difference of what was on my contract versus what i had been paid as well as sort out my query. When i called back the person dealing with my situation does not answer or exist anymore. My id number is available on request, i worked for edcon under the brands division River Island. Regards phike tshoke