Tata Docomo — about unwanted deduction of Rs 165 Rs

My account is debited by 165/- Rs . On 8 Sept 2013. I having sufficient data balence in my account but when i was closed internet then i get massage about deduction and it is of 165 Rs. I call customer care on 198 for registring complain but customer care executive said me that if data balence is under 25 Mb then their system directly debited from customers main balence for security. Nice joke na? But it's true. I always use internet packs and then use internet and also cheke data balence before browsing. But this telecom sector are always search new techniqes to give pain to us. So I request you please give me the parmenant solution for this complain. Thanks