Bad Service

I've received a call that my loan is in arrears and that was 3 or 4 months ago. I asked how? Reason being I am paying more than my monthly premium of R1381. I am paying R1400. I've received another call today and I have been trying to sort thsi mess with Nelspruit branch to no avail. STD bank does not know my monthly installment. I need this **** sorted out but they cannot. Thabisile Nkosi (debt collector) told me that they cannot they ownership of this mess and sort it and that I must always go to the branch and sort it out. I told her that I've been there on numerous occassions but I did not get any assistance.