When shipping a return item to us, you must properly package said item to prevent any damage in transit. It is a good idea to re-use the original packaging, if you still have it. Otherwise, you should aim for the standard of packaging when you received the item. The box should be close fitting and use extra packaging to absorb any bumps in transit. Large items, especially, should be packaged with care to prepare for the worst.
We have an OcUK Academy tutorial video with further details on how to properly package a PC.
https://youtu.be/NET8RtcxSus?si=iUn2Gx2A01PgaXWj
If damage should occur during transit and we have arranged the Return Label or Collection, then the burden will fall on us. We will, however, only honour the RMA process if the item has been properly packaged, as detailed above.