Service request repeatedly ignored

On Wednesday 18 February I was informed via sms that a cheque paid into my account had been reversed. When I first called, the call centre aide could not tell me anything about the cheque. The 2nd time I called, I was told it referred to a cheque deposited into my account on 2 September 2014 - how can a cheque paid into my account 6 months ago suddenly be dishonoured?? Surely there is a time limit - how does one assure yourself a cheque has 'cleared' and deliver goods (for instance) if the cheque can be written back 6 months after the fact?<br> I raised a query and received an sms to say that the matter would be resolved by Tuesday 24 February, but I received absolutely no communication from Standard Bank. When I called again on Wednesday 25 February I was told that a service centre worker had contacted me (an outright lie - I'd love to hear a recording of the message or conversation?) but that the matter would be 'escalated' to the 'back office' and that I would receive a reply very soon - it is now again more than a week later and I still have not had a response. Your service is shocking - after 20 years I am now seriously considering moving my account.