"This item is used and we unable to do test"
translated to: we tested it but... (1) we dont know how to fix it, (2) no spare part available for replacement, (3) this item is heavily damaged beyond repair.
(4) We used it as a parts donor to repair another item.
(5) A lot of smoke came out of it when we turned it on, so we didn't bother testing.
(6) It is so dirty/contaminated, no one here dared to touch it.