On my listings, I have specified that insurance is 'included in shipping', rather than 'required'. Insurance is required in both cases, but this presents it as a service to the customer, which is better way of presenting it since buyers do not like to be required to do something.
If there is a discrepancy between listing and invoice in the way these items are presented, I am sure there is a reasonable explanation, which may even include an honest error. To blatantly accuse the staff of Auctiva of scamming people is irresponsible at best.