Bad service

Good day

I am battling since August 2019 to get a response out of Spot on Cleaners. they submitted a IRP5 for my son in 2*** financial year whilst he was not working there anymore. Sars wants my son to pay them r8000 +- because of their mistake. they only come with excuses but not answers. I gave them the option to pay Sars the money or reverse their IRP 5 but to no avail. Meanwhile my son is stressing because he hasn't got that kind of money.

please advice.