Problem
An elderly Greek couple, Mr and Mrs Kyrgios, with little understanding of written English or formal education, signed a guarantee and mortgage over a block of shops to the Commercial Bank as security for payment of the debts of their son's company. Their son was a property developer and builder. At the time of signing, they were led to believe by their son that the guarantee and mortgage were up to $50,000 and limited to six months. They were also told by their son that the company was in good financial condition when in fact, it was in serious financial trouble.
When the bank manager brought the papers to Mr and Mrs Krygios's home for them to sign the mortgage and guarantee, he corrected their misunderstanding about the length of time the guarantee was to run for, explaining that it was for an unlimited time and not six months. However, he didn't explain the possible effects of the documents, which Krygios could not read, and he did not mention the fact that the amount guaranteed was unlimited. When the son's company went into liquidation and the bank attempted to exercise its rights under the mortgage/guarantee, the Krygios's attempted to have the contract set aside.
Task
Do the Kyrgios's have any claim against the Bank under the Australian Consumer Law? If yes, under what basis can they claim?