Hi Glitter,
The only way I was able to get my issue resolved was by escalating it to the Australian Financial Complaints Authority (AFCA) as well. Once AFCA became involved, the matter was resolved quite quickly. You can also lodge the complaint online through AFCA.
Before taking that step, I made every effort to work directly with MYOB and exhausted all available options, but unfortunately got nowhere.
I found MYOB extremely frustrating to deal with. When customers have a genuine complaint, there appears to be no resolution process, leaving them with little choice but to escalate the matter externally through AFCA.