Landlord Overcharging Utilities (Electricity & Water)

Hi, it's been two months since I moved into a subdivided flat and I got my first utility bill from the landlord yesterday. I'm sure I'm being ripped off here but I don't know what I can do about it.

There are three subdivided flats (one bigger and two smaller ones) and they all have their own 'unofficial' electricity and water metres installed by the landlord. These are to read how much electricity and water each of us are consuming, and to charge us a fixed rate as stated by the tenancy agreement. She receives bills under her name based on the 'official' metres installed by HK Electric and Water Department.

In the first month, I used 300 units of electricity. She charged HKD450 (HKD1.5 per unit), which should have been HKD300 according to HK Electric's block rate system. This is 50% higher than what I should be paying for (even worse with water).

I told the agency that it's not right for her to make a profit out of utility charges. He said he will talk to her and get back to me in a couple of days.

I would appreciate any comment on this... What else can I do?