Standard Bank

My mom and I invested with Standard Bank 5 years ago. She invested with R50.000 then she was suppose to receive an investment of R50.000 which in total was going to be R100.000 but she went to check early this year and the investment was only R16.000 instead of the total of R100.000. When we ask they tell us to be grateful that we still have the money. The investment company was changed without any of us signatures or informing us of theses changes which means its ***** and we need help because the end period is this year April.