Dyson V15 Vacuum Replacement Dispute Unresolved

It's been around a year since I bought the Dyson V15 cordless vacuum cleaner. Recently, it started leaking felts and blowing air from the sides. After sending it for servicing, a replacement was approved. However, since I purchased the product from Teknosa, they informed me that the replacement would also be handled by them. Upon visiting Teknosa with the replacement authorization, they stated they didn't have the item in stock and could only offer a gift voucher equivalent to the amount paid on the day of purchase.

Currently, Dyson customer service insists that Teknosa should resolve the issue since they received the money, while Teknosa claims they don't have the product in stock. Dyson's customer service further mentioned that they handle replacements immediately if the product is purchased from their own stores, but if purchased elsewhere, it's not their concern. Did Teknosa outsource this product? If Dyson manufactured it, why aren't they taking responsibility? I demand a swift resolution to my predicament.