Well in a fit of righteous indignation, I messaged the seller thus:
"Hello,
Following a protracted processing time for this item (purchased 6th October 2021), you have sent a message (dated 16th October 2021) about the item being 'defective' and offering what amounts to 'store credit' rather than a full refund of the purchase price.
For your information, I am fully aware that this particular 'selling practise' is now becoming very common with items of this type on Ebay.
As you have already informed me that I will not be receiving the above product which I purchased in good faith from you, and which your listing suggests is 'in stock', I am considering your message as notice of 'item not received' and informing you of such. I would now like an immediate refund in full, or I will be escalating the matter with Ebay at the earliest opportunity.
I should also like it to be noted that I am *not* asking that the transaction be canceled, and I have not done so at any point in our communications. You, the seller, are the party who is unable to fulfill their side of this purchase agreement.
Thank you."
A bit snotty, but still within the bounds of legally-formal politeness. I don't really care if they understand the nuances or not, but I look forward to him cursing my descendants
and my ancestors soon.
I bypassed Messages, and sent it through the order details page using 'Ask the seller a question', which will hopefully give me the option to escalate after 7 days. The most important thing is that Ebay will see the above message if it does escalate. So we'll see what happens. I don't want to wait until
January 2022 to sort out this shenanigans.
But yeah, this is feeling very much like the last time I'll be using unfamiliar sellers on Ebay and AliEx, even if the list of trusted sellers is near-microscopic.