If the link will not work open ebuyer in your browser and log in you should now get your account screen scroll down till you get to returns and click on the number under request number the screen will show you your returns request you will need to make a note of the RMA number on the right of the screen. Yuo need to write this on the outside of the parcel along with their address. The email will explain the rest hope it sorts.
They have discontinued their phone service cos it was crap.
You can also send then E notes from your account screen but be prepared to wait for a reply.