Capfin selling paid off debt to collection agency!!!!!

I had a personal loan with Capfin which I paid off and settled with MBD Attorneys in June 2015. To my surprise I requested my credit report and Capfin has now sold the same debt to DMC in August 2017 and it is reflecting that I owe Capfin and the account is in arrears. I am really appalled that they confirmed that I have paid them in 2015 but had the audacity to still sell that debt to another collection agency. Now my credit score and report have negative reports which is affecting me negatively. The National Credit Regulator needs intervene because the companies are only interested in falsify information on our reports and cant fix the problem immediately. I must wait for 21 days for them to update my report with the bureau, this is totally unacceptable.