if your gross value of FBT is 17k, you'll find that only the taxable portion of that (around 51.5%) classifies as taxable income, so the overpayment won't be AS bad.

unfortunately, ignorance won't be taken into account, however, if you've not seen any benefit from that $17k value (so the employer hasn't paid anything at all to you or towards what would be deemed your fringe benefit (mortgage payments, car payments etc) i'd be appealing it to the hilt with the employer!