I bought software from kinguin. They added a payment charge from paypal. Paypal told me they thought this was dishonest but they don't do anything about it. When I queried it the charge was noted as $1.75 but in the bill magically transformed to $1.92!
Not sure if ACCC and the ACL prevent such charges unless disclosed at time of sale as a sneaky misrepresentation.
I rang ACCC and they confirmed that this was misleading and I had a case. Posted for the benefit of all who buy from kinguin. I ahve written to kinguin to ask for a refund as well.
If you didn't authorise the charge then just get a chargeback from your credit card company.