I have searched and searched and can't find any information on this. Is there a way to unbiolink something that is biolinked?

Delete it and send in a ticket saying it was an accident. I do it all the time.

Do they always give you the item back?

Just tried it, the item was returned still bio linked

the only way to do it its with server transfer when u move toon all biolinked items become unlinked :) no other way

bio links are real annoying and i know theres no way to un biolink a biolinked item

FOR SELLING:
Not true anymore, Friend attempted the ol' Sunriders Destiny xfer trick, After xfering the item stated Unknown vice resetting like it used to. When contacting GM's they stated that the only way to fix this is to transfer the toon of who it belonged to and submit a ticket referencing the current ticket being addressed and they would re-bioling that item to that toon for you.

WANTING TO RE-BIOLINK FOR YOUR OWN TOON:
Depends on what GM you get, Mr. Nice guy or the A-Hole who will tell you you are out of luck. If he is working with you he will log on to meet the toon you want it on and watch you Re-Biolink the item on the spot.

I have seen all of the above happen.