account handover

I have been paying my loan and it is up to date, yet standard bank decides to handover my account to a debt collection company, I fail to understand why and this is totally unacceptable. You are creating a bad name for me and I will not tolerate this, I called and asked that my account should be taken back from them and they said it was done and it was handed over by mistake, now I get an sms saying my account has been handed over. I will not pay this account or any other debt collection charges that may incur, plz just fix this