Mahanagar Gas — higher billing for the month of dec'18

I am an existing customer of mgl. I received mgl bill for the month of dec’18 for rs. 28, 699/- which is very huge & not acceptable at all. My previous bills were for the month of aug’18 & oct’18 of rs. 222/- & rs. 1321/- respectively. My ca no. Is[protected]. Request to look into this and help in getting the issue solved & please send rectified bill for this month, dec’18.