Issue with gas&electricity yearly bill

hi guys,

This is my first year in Brussels and so far I have experienced all different kinds of challenges,and new one is right there up at the horizon in the shape of - MY FIRST YEARLY OVERVIEW OF ELECTRICITY AND GAS USAGE.

In the apartment where I live alone the calculation for the last year Sep18-Sep19 is that on the provision I am already paying 70e I should pay +600e extra! This amount is exceeding all my expectation given the fact that I am not using much gas on heating (I dont like sleeping in the heated rooms) and that I do not spend much time at home.

I had the talk with engie client service and they have agreed that it is too much indeed but I still have to pay the price since they see the usage on the meater like that.
In the last 10days since the last measurement the usage is very very high and I only use gas for my bolier to heat the water for showering.

Did any of you have some similar experience? What would be my next step?
I have contacted my landlord asking for support and arranging some technician to come and do the check. If the gas is leaking somewhere that could really be a big risk for all of us in the building. I do not smell it tho , so I hope that is not the problem.

At the moment, I am out of ideas and I am coming to you for support!
thank you !!