If it was made under a previous agreement, like terms and conditions yes. Internal policy is just what they do internally and pretty much can change any time. If you agreed to something sure, but they never had that afaik and I can't find a terms and conditions on their current new site nor a published refund policy beyond the first 30 days thing. Though I've been told that none of these companies (SS, PCS, etc) follow FTC's FTC's Mail, Internet, or Telephone Order Merchandise Rule. However I'm not really sure how it works with preorder items.
If so you could file a complaint with the FTC I guess however I don't know if it'll actually work however it is relatively easy. Also be aware that they are under no obligation to sell you ----. They can refuse to sell you goods unless under specific reasons (discrimination of race etc). So if you do that and they decide to cancel every single one of your orders and refund you and tell you to ---- off they totally can, so tread lightly if you want to order new stuff.
You can also go to small claims court but you'd have to go in CA and it's kinda a waste of time for $95 unless you feel like you want to stand for it
It sucks, but also I can understand cancelling preorders. The whole "oh I'm cancelling cause the delays have made me lose interest" is the worst excuse I've ever seen. It means you were weak and bought it on a whim and you should be ashamed of yourself for your lack of self control (I have done the same thing, and hang my head :P). I've you've been in this hobby for any amount of time you know the wait is long, you know there is delays. It's a reality of the hobby that we're familiar with. If you're new (we're all new at some point) and don't actually know that's something though you should probably do a little research before you throw down that kind of money.
If you need to refund cause of hard times or something that really sucks
Selling PO's isn't that lucrative anymore but you can likely get your money back hopefully, try the facebook BST groups be a little patient and go through PP invoices. Also be clear it is a transfer and that PCS will actually transfer it to the buyer and they can receive confirmation of that. Some people don't know that.
Some people also don't read as I sold a PO once (wasn't interested anymore, as I said I also hang my head in shame :P) and the guy later asked me where it was. I ----ing highlighted and bolded that it was a PO transfer and that it was likely far away. And I had copied him on the request to get it transferred and it was no longer in my hands. I told him he could have it transferred back and I would refund him but he said nothing cause he was too lazy (hell to ----ing lazy to read so I dunno what I expected :P) and I never heard from him again so v0v I guess.