Have not received per diem?

My Husband just returned home from Iraq in February and has yet to receive his per diem pay. Everybody else received theirs around sometime in March. We finally figured out around April that the person that did the paper work messed up on his paper work somehow, and that's why we never received the money. Well to make a long story short, my Husband had all the paper work redone and whatever else that needed to be done for it, and here we are and we haven't received it! Today he got a text from his Sgt saying his Platoon Sgt needed to talk to him in regards to it. My Husband told me that probably doesn't mean anything good for us. I'm just worried, because we really need this money...and if we are not able to get it for some other stupid reason, I just don't understand why we wouldn't be able to receive it? He's entitled to it. And need I mention, he's the only one in the company that had this happen. It's frustrating. Any ideas on what could be going on, that is stopping us from being able to get it?? I mean, my Husband can't make them give it to us, if they won't..