balance deducted in mts sim

My mts no is 8502869939 i have the balance of around rs 300 before 20 days today my balance come to zero then i talk to customer care they told me of activating of some news but actually i didn’t activated any news services on my number and i think company deduct around rs 200 from my number now they are not returning my balance .now i need my balance back to my number so please redress my problem .thank in advance