If you are returning an item for the reason item not as described, if the seller does not send a pre paid return label within 3 days, then they do not want the item sending back, sometimes it's just not worth the postage cost.
If there is no refund within those 3 days, then just escalate the case, and eBay step in and force the refund.
I do not know the reason for the return, but if you have selected the reason ... Does Not Fit, or Change of Mind, then you have to pay for the tracked return postage label.
@68fiona