The website simply says "Temporarily out of stock"
I ordered before v4 was released, and I also contacted them about a month ago to ask for a refund but was told I could not do so until the mandatory 8 week estimated delivery window had passed.
I'm not mad, but it is obvious to me that they had no capability or intention to fulfil my order and were just hanging onto the €. They also sent me an email (before I cancelled) saying I could turn my current order into credit for a v4 preorder.
Edit: Checked their shop and now says Out of Stock: https://shop.fairphone.com/en/fairphone-3-plus
You might have gotten unlucky on timing right at the end of orders.