RockAuto was very easy to deal with. I initiated a refund online, answered a few questions and within two minutes had this:
"Your refund will be issued within 1-3 business days. We will email you when the Refund is issued.
If you still need a part, please place a new order. We do not need you to return your problem part now, but please keep it for two weeks; we may ask you to send it back."
I do have a filter cutter and will dissect the filter in two weeks. I will take some pics and report back then