Wesco — Clearance certificate regarding previously staying quarter

Sir,
I am residance of burla, sambalpur.
Today i went to wesco office for clearance of my previously staying quarter but they told me that i have some arrear amount to clear. But when i enquired about it i found that some person forcefully occupied that quarter and using electricity. But while i left that quarter at that i have cleared all my dues. Again that quarter is not alloted in my name as i have vacate that quarter and i have the quarter clearance certificate from my office.
Now they are saying to clear that arrear amount.

Please sir help me as i am unsatisfied with reply from wesco.