Biggest ******* ever

I had invested around 4 years ago with Amathuba and signed up for R150 a month after receiving a call what a great investment this was. Little did i know what a big ******* this was. My investment went on constant downhill untill finally i decided to cancel. They cancel and tell me i will receive my money back in 6 months. Finally they deposit and guess what i receive after almost 4 years, R745! The last time i checked my investment well over a year ago it was around R3000. How is this possible now i cant get hold off anyone in amathuba to give me an answer. Pls dont invest with these guys the service is bad and they also debit your account in error.