[mothered]

they keep asking for videos Even after I sent them corrupted files, they told me to upload the video kn YT and give'em the link.

Compliance Is Imperative. This gives the Impression that you're doing your utmost best to fulfill their requests and resolve the Issue.

Do as they ask and upload a video on YouTube. It doesn't need to be corrupted, but more so to the point where It's not viewable. For example, the video has a static effect that gives no Indication of It's contents. Claim an authoritative figure and express your frustration that you've done everything as asked to no avail, and you'd like the matter sorted asap.

Now I am thinking about boxing them. Do I have any chance? Also, what can I put in the box to make it look legit, because the damn wheel has 8 fcking kilos?

Stating the obvious, the dry Ice method.

Of course (and given the Item Is quite heavy), you need to weigh up the cost of the dry Ice against the entire cost of the SE.