the information usually states how to return the product. RMA clearly on the outside of the packaging and on the inside via a note.
rotters
I wrapped the box in an extra layer of cardboard and put the sticker on that along with the RMA number in big letters with a marker pen.
Who did you use to send it back? I got one as doesn't fit the H100i
I used Parcelfriend. Cost about £9 for them to collect from me and deliver next day.