How would you punctuate a sentence that's half question and half statement?

[KostasKouvalis]

"What exactly was the cause of the complaint?, because I see nothing wrong here.

[Daisy_Bojangle2]

Just switch it - I see nothing wrong here. What exactly was the cause of the complaint?

[Daisy_Bojangle2]

Or alternatively replace the '.' with a ','

[KostasKouvalis]

That works

[NewsReader]

What exactly was the cause of the complaint? I see nothing wrong here.

[KostasKouvalis]

Oh, it was about that new ASK bar they implemented, but it's been resolved now

[Guy13]

That is bad grammar. Remove because and comma from the sentences.

[KostasKouvalis]

How's it supposed to look?

[LiamJHayden]

Either "What exactly was the cause of the complaint, because I see nothing wrong here?" or split it into a question and then a statement.