bad service from head office payroll department

I am an ex employee of the company whose position had been effected due to the re structure. I had taken the voluntary severance package that was offered to me in the month of September. The amount that has been paid out to me and the amounts stipulated on the documents I received do not correspond. I have made many queries and sent emails to the relavent person(s) at the HR department at head office but only one issue raised has been resolved and this infact took one month... I still am facing an issue of a minus reflecting on my payslip which cannot be accounted for. As per the payroll officer she claims I have been paid in full but I have already explained to her that they are in breach of contract according to the documentation I signed , the amounts and the dates of payment which was made is incorrect. Unfortunatley I cannot get any help from her.Can someone please assist me