Getting pissed at rock Auto

Have you gone to the KB - Silvolite web site and tried ordering the .020 os pistons directly from the manufacturer.
More than likely your pistons have not shipped because RA is finding the same thing that you already found, no one has .020 os pistons in stock.
That is why it is always best to have the pistons (and rings) in hand prior to machining the bores. Now you know why.
I know you said you did not know how much it would take to clean the bores up, any competent MS would be able to do that.
When you get to the RA ‘Attendant’ recording. Leave a voice message, try to contain the anger and leave a reasonable inquiry with a return phone number, I bet you get a call back.