KW Eden erroneous bookkeeping

I rented a property for a period of 2 years via KW Eden (ACT Property Management). At the end of the period, when the owner decided to withdraw the property, KW Eden had to return my Deposit of more than R26300 (inc interest). They only repaid me R19857 although the reconciliation showed that over the period, I actually paid R1600 more than required. They claim that their bookkeeping system - WeconnectU - is correct and refuses to do an actual hand reconciliation, which I did provide. They went as far as to add invoices to try and recon their errors and thus just added more ******* items. I speak for numerous tenants who have had the same experience with ACT / KW Eden