Did some digging into this whole "Ujin missing" situation and found this:
Click to expand, or just click the thumb to open it in a new tab.
89Land is a Ujin fansite, so... grain of salt. In short, this translation from the site details fan-cafe drama, reveals Ujin left the company in the end of May, and claims the company is trying to hide the truth.
The company describes Ujin as a selfish, non-caring person who refused to participate in D-unit activities.
It's all basically a clusterfuck. Rumours, fans against the company, etc etc. Remains to be seen what'll happen to D-unit in the long run, but at least Zin has the solo single coming out in few days and whatnot...