Seller closed return today 8th september although he did not provide return detailshow to reopen return?

Well, sellers need to accept the return of wrong items and send a prepaid return label. If they don't, you can ask eBay to step in on day 4. https://www.ebay.com/help/buying/returns-items-not-received-refunds-buyers/ask-ebay-step-help-buyers?id=4701