African Bank and MBD

I currently have a loan with African bank their debt collector MBD is very rude this lady is calling my work everyday I am trying to make payment arrangements but she is very rude..Because my account is in arrears does not mean u need to call me and be rude to me ,threaten me ,harras me No.I refuse !..Also I currently have a loan with standard bank I am paying through MBD n I never experienced problems with consultants calling on Behalf of standard bank from MBD but with African bank I am being harassed !Standard bank is the best n they are professional unlike African bank with their rude n insensitive consultants from MBD