Jetstar cancelled my flights and told me I could have a refund but sent me a voucher instead.

Jetstar cancelled my flights to Bali on 1 October. I contacted live chat and asked for a refund. They agreed to a refund and said it would take 15 days. On 8 October they sent me a voucher. I again contacted live chat who refused to refund me even though I had it in writing. Jetstar also refunded me for Bangkok flights that they cancelled in June. This is the same circumstances and I believe they are guilty of deceptive conduct under the ACCC guidlines. The voucher is for $2337 which is too much to spend on domestic travel. This is no way to treat a loyal customer.