Does any one know how long it takes to get LIN from NSC

[sardar]

I have applied for extension of B visa on dec 2nd( Reached NSC 3rd ) ; 
Check  is not cleared  yet ;   My 1-94 expires on 12/15; 
Do you think  i should be ok  ? 
or concered since my check is not cleared yet ;

Please let me know  what is the safe date i can wait 

If  nothing happens, Do you know  whom to call ?  

or should i   fill in Online i-539  Since i have very less time 

Thanks

 :confused: