Immigration letter

Made an error on an immigration form online, and they've sent back a letter saying they're intending on refusing the visa.
I need to write a letter stating that I misunderstood the question, the question asked if I have been refused or cancel a visa to Australia, I thought the question said have you had a visa cancelled, previously I did answer a few questions above saying that I had previously applied to Australia.
Need help to reply by tomorrow to avoid refusal