Seems that they don't pay back the fund to the address which coins had been sent from. They send back bitcoins only to the coinbase wallet...
So, no one should use Overstock. Because they only refund bitcoins to coinbase wallet and the user will have to pass KYC in coinbase to withdraw bitcoins.
What a strange business policy, as if someone wants to show how complicated it is to pay something with BTC. Although I've never used Overstock, this is a good warning to stay away from companies like this.
As for CoinPayments, I've used them a lot in the past - I've even been in their signature campaign. What I do know is that any seller can set a time in which payment must be made, and few times I also missed that timeline. In this case, it is best to contact the seller directly because he can manually extend the time and accept the transaction, or ask for a refund from CoinPayments, which in some cases will not be possible if it is a very small amount.
vegasreb, can you try to ask Overstock to manually extend time for your payment on CoinPayments which would completely solve your problem. They will get BTC, you get your order and there is no need for refund.