21-10-2017 11:32 AM
It sounds to me as if you requested a "return" [where the seller does not have to send the postage] and not a "not as described" case [where the seller does have to pay the return postage].
The system is that when you open the not as described case the seller sends a return post label. If they do not then you escalate the case after 8 days and eBay steps in. There is no way to speed things up and certainly you do not post it yourself.
As advised if you did do that there is no obligation for the seller to refund the post and certainly not through eBay.
There is no facility to get a refund on return postage after the event.
You should have opened a return case and the seller would have given you a returns label, if they didn't ebay would have issued one at the sellers expense.