Seller has mixed up her items and sent them to the wrong buyers.
She has requested I return the item, once it arrives, at my expense.
However, the parcel hasn't arrived and I'm going on holiday today. The item needs returning within five days and I’m not here to do that. If it isn't returned my money will be released to her.
Seller has the option to offer that I keep the item without paying for it.
As this is the sellers mistake is it unreasonable, to ask that I keep the item and she refunds me. When I get back from my holiday, I will return it to her at that point.
My thinking is even if I mark this as having an issue this sale is going to complete within the set five days, meaning I'm going to pay for an item I neither ordered or want. ( and haven't seen, don't know the size, etc ).