Blac Chyna has a serious hacker problem on her hands ... and if some exposed messages ring true, she's not going down in her trademark battle with Kim, Khloe and Kourtney without a fight.

Chyna posted a video Saturday claiming her Instagram page had been hacked. The page posted numerous private text conversations allegedly between Chyna and her attorney discussing the trademark battle.

One message -- allegedly sent from Chyna last week -- reads, "When I get married 7-17-17, I will just trademark it then ... But f*** it ... I'm not going to ask Kris ... Is it easier when I'm married?"

The hack doesn't end there ... there's also a thread of messages supposedly between Chyna and Young Thug that get flirty and a thread with Chyna and Jayden Smith that mentions Kylie and Tyga.

However -- there's no date stamp on those messages -- so it's unclear if the alleged texts were sent while Chyna was with Rob.

BC has since created another Instagram account, but as of now the hacked one remains active.