outstanding balance

I was listed as a slow payer by blue finance and a lady by the name of TSHEPO MUKANSI and I made payment arrangement with her I asked her to debit on the 15th of every month and she said my last payment will be May 2016 , but now 3 months later they started making debits on the 13th of every month I then went to my bank and stopped the debit because I couldn't get hold of the number they provided . Tshepo called me regarding my payment and I explained why I stopped the debit my problem is that I asked her to sent me my statement of account and she told me that they lost all the information due to the load shedding last year , I feel like I'm paying for a debt that I finished a long time ago please help I don't know what to do should I continue paying them or I should stop.