SARS ignoring all correspondence on helping me with bad debt from 15 years ago

I have been handed over for debt that was written off by SARS. The debt was R30000 and now it is R85900. They have been deducting from my paysheet R1500 for 7 months and it is so bad that I can't buy food. I got someone to assist me but SARS is just ignoring all correspondence. They blacklisted me for R85000 about 7 months ago and now I got a sms I still owe them R85900. It wasn't my fault that I got in arrears as my employer gave me 4 payslips 15 years ago and they added the tax individualy then SARS came and calculated all income together and that is how I got to owe SARS and they just keep adding money even if my pay is not enough to qualify for paying tax. It looks like I am going to pay SARS for the rest of my life as no one from SARS reply on our e-mails and how can they write off debt and then reinstate it again. Can someone please reply on this ridiculous amount I owe as I don't even have food in my house.