query orwhere creating problem

here is my query

       $count = DB::table('processed_applicants')
                 ->whereBetween('accept',[0,2])
                 ->where('expiry','>=',carbon::now())
                 ->whereNull('expiry')
                 ->where('jobpostingid',$id)
                 ->take(9)
                 ->get();

suppose i have id (example)=j100,j1005 of table jobpost and i also want to keep record of rejected applicants form in processed_applicants table belongs to particular id . so i add a column name (expiry) intially expiry contain null value but if admin reject this id=a102 then i m adding a carbon::now->addHours(6) in column expiry now i m try to display this value if it contain null then accept button is shown else reselect button show be visible my above code is working little properly result is show to id J105 also which i don't want

eg

1. J100

        1. a102 ---------> null value entry in rejected column
        2. a103--------> it have expiry date time entry in rejected column

2 . J105

        1. a101   ---------> null value entry in rejected column
        2. a100 ---------> null value entry in rejected column

now J100 can see a102, a103 but don't see a101,100 above query working perfectly fine if i remove or where