Before this article gets also deleted:
http://en.itar-tass.com/world/738262The proof that the rebels had indeed a Buk missile defense system.
DONETSK, June 29, /ITAR-TASS/. Self-defence forces of the Donetsk Peoples Republic have taken control over a missile defence army unit equipped with Buk missile defence systems, the press service of the Donetsk Peoples Republic told Itar-Tass on Sunday.
Why are they now claiming they don't have it ?
Because if Ukraine can prove the rebels didn't take it from them, it means they must have gotten it from Russia.