Hi I have the same problem. what does NULL means and succes find: 0 items! means?

I ordered in aliexpress online store with 4 different suppliers.
1. RB743944165CN - status on aug. 18 is departure from outward office exchange - what does this means?
2. RB333268416CN - this is the tracking num the supplier gave me and it's the 4th day now. the result is 0 items ! does this means no item has been shipped? I'm getting worried about it because the supplier is no t replying. may be you can help me track my item.
3. RB738726176CN - same with this one it's the 4th day now, whe I tracked it the result is success find: 0 items ! does this means no items where shipped? I ordered 11 items from this supplier so I am worried about this.
4. RB185490512CN - the status is NULL and the location is CAN? what does NULL means and where is CAN? I ordered 2 items from this supplier. will I expect a problem?