Have you received the collection code to collect your item from store? The store cannot find the item or release it, without this.
Check your order details it might be there, if not, you need to contact eBay Customer Services they will provide the code for you.
I do hope 7 days haven't lapsed from your notification that the item is in store, that's the time a store will hold an item, after that, they can dispose of it as they wish.
To Contact Customer Services, I find the quickest way to contact them, either for a Live Chat, or you can select to speak and request a Call Back, to click on this link:
https://www.ebay.co.uk/help/eua?id=5275&mkevt=1&mkpid
On weekdays lines open between 8 a.m. and 10 p.m.
On weekends they open between 9 a.m. and 6 p.m.
@geoff8375