Two different amounts smsed within 24hrs

On the 18th January 2016 08:03am, I received an sms from e-siyakhokha saying the amount due on the 4/02/2016 is R1023.00. Then today the 19th January 2016 08:11am I receive another one saying amount due on the 04/02/2016 its R1655. I need to know how does it happen that two different amounts are smsed to me within 24hours. which amount must I pay between the two. Again I have a problem with systems that are not talking to each other. Account number ***.