Well , you are correct don't send any additional documents unless you know what's happening.
What you can do at the moment is keeping nagging on gcmsbuddy and get them to file a complaint, usually delayed GCMS notes can only be beacuse your file is currently being looked at and hence the officer won't release it unless it's either processed or further information is requested from you. This can be true for when your file is in background check stage.
With that being said, if your POF wasn't good enough to start with ( unjustified balance, improper documentation ..etc) then by then you would have either got an ADR or straight out refusal (which I hope will NEVER happen to you).
One more thing, try to call them again and see if you can get more information about what is wrong with your POF ( TRUST ME, they can read out the notes just like you do when you get them, they sometimes don't like to do it)
How can he try to call them? On which number?