Hidden interest

Vodacom accounts appear incorrect on the client side - not showing the correct balance. Client has been paying the account as per the received statements. Received sms stating he is in arrears. After calling the callcentre he was assured that the account was fine and that the outstanding balances is only R3. Account was still suspended and after numerous calls it was confirmed that the statements on the clients side is incorrect and that he has been in arrears for quite some time. The concerns are that the account would have been settled months ago if the balances showed, however it is concealed and does not show that there is a debit and thus vodacom has been adding interest in the background. If this has been happening on all accounts in arrears vodacom could be earning millions in interest hidden on the clients invoices and statements. This is unacceptable.