If the price on the website was better than that which the telephone agents could give, why did you actually purchase over the phone rather than the website?

The agent on the phone may have been trying to come up with logical reasons why there was a difference but would be better if the agent had just said "I don't know" , but other than that I don't see what wrong has been done

You did agree to purchase a ticket at the price quoted over the phone and there is no entitlement to refunds on purchases of goods based on change of mind in Australia