Cardi B Claims Hack Responsible for Offset's 'Miss u' DM to Tekashi69's GF

Cardi B says whoever was messaging Tekashi 6ix9ine's girlfriend certainly wasn't her hubby, Offset, and she's out to prove the whole thing is just some bulls**t.

Here's the deal ... Jade -- who's dating Tekashi and who Cardi allegedly ordered an attack on in August 2018 for sleeping with Offset -- put Offset on blast for apparently sending her a DM on Instagram saying "Miss you fr."

Jade shared video of her checking her phone to show it definitely came from Offset's account, and poured gasoline on the fiery situation by adding ... "Your wife @iamcardib has a OPEN CRIMINAL CASE , why are you writing me you don’t respect her ???????"

The thing is ... Cardi and Offset say it's not real -- they claim he was hacked. To prove it, Cardi's shared a couple of vids with Offset, saying they were up sick with their kid all night ... and insisting her husband didn't do what Jade claims.

She also revealed a couple of screenshots from Twitter and Instagram, seemingly proving he was hacked and is unable to log in to his accounts.

There's also this -- earlier on Tuesday, around the same time Jade made claims Offset was messaging her ... his Twitter account was tweeting some strange tweets, including one that just said "I lick ass cheeks."

So, it seems like something suspicious is afoot ... it's just unclear who's to blame for starting it.

One thing to note ... Jade suggested she has more dirt on Offset, saying, "Theirs a lot of s**t I haven't exposed yet."

Stay tuned!