Selling "Used" Shoes and make it your Problem when it doesn't Fit.

I bought Nike Men's Quest 6 Road Running Shoes - White/Black/Hyper Royal/Volt - UK 10.5 returned the product 7 day's after delivery and Note I was not home on delivery there were people to receive on my behalf. When I fitted the shoes it did not fit the same than the Nike Men's Downshifter 13 Road Running Shoes - Ashen Slate/Obsidian/Sail/Pure/Platinum - UK10.5 that I bought August 2024. I returned the product, received correspondence 4 days after return lodge "Unfortunately, we cannot accept your return request as the item has been used." The one shoe did have a bucle in the middle and the other shoe was brand new as if they send me the shoes been used to fit in store. How am I supposed to wear shoes that does not fit, as they said it was used. I will completely understand if I requested a refund and not a upsize replacement.