No. The label will expire in a few days - it will state on the botton when it needs to be used by.
If you don't use a Simple Delivery label, the buyer gets a refund (after about 30 days). You could hang onto the item then pay to send it in a fortnight.
Personally, I would be tempted to cancel the sale and relist when the buyer is able to receive it, otherwise Ebay will nag you to send it and it may have an effect on your account because of late posting.
"There are two ways to be fooled. One is to believe what isn't true; the other is to refuse to believe what is true.”
Søren Kierkegaard, Danish philosopher (1813 - 1855)
