我们不清楚您到底是怎么想的。
It is not (quite) clear to us what you had in mind.
It is not clear to us what you meant.
It is not clear to us what you intended.
使我们担心的一点是……
The one point that concerned us (a little) was... *concern “担心,在意”。
The one point that troubled us was...
我们对……感到担心和挂念。
We have become concerned with regards to...
We have become concerned with regards to the shipment schedule. (我们对装船的日程感到担心和挂念。)