[al2o3cr]

IMO it sounds like you've interpreted "pre-order sales" very differently than Shopify does. The below references this document:

https://help.shopify.com/themes/customization/products/allow...

"Pre-order" in that document appears to refer to products that authorize (make a "pending charge") at checkout but capture (make a real charge) later - the merchant doesn't receive the money until the capture, when the product ships. How far apart in time these two events can be depends on the processor's contracts with the rest of the upstream network; the Shopify doc specifically lists a maximum of 7 days. The Guru post mentions "capturing but delivering later", but how much later is unclear.

Combine that with the "no refunds after September 29th as the money will be gone" policy which seems (IMO, IANAL) in opposition to chargeback policy from the card networks and I can totally see why Shopify might not want to carry the risk of your customers.

Also, if this is the first time you've interacted with Shopify support you should've spent some of that "year of development and planning" making sure your partners were 100% on board...