Two debt collectors on one account

I was handed over for my account, I made arrangement with SDK ***) to debit R250.00 on my account. To my surprise I was also chased by Vericred ***) for the same account and I finally agree to pay R250.00 through debit. Currently two debt collectors are being paid for this account. I recently phoned both companies to check the balance where I found that SDK balance is R270.00 and Vericred is more than R2000.00. Can you kindly assist to sort out this mess because I have been paying for longer now. if all collections were being paid to you by these companies I should have been done by now. I have prove because I pay though debit.