total income= 28750
tax payable on income =(28570-18200)*0.19=1970
add in franking credits, 1970-8570=-6600, (yes a rebate)
Add medicare levy 0.02*28570=571
Total tax payable=-6600+571=-6029
You should receive a rebate of 6029
There may also be some other calculations but this is basically it
