National Grid this company bill me for shut off gas and electric meters Utica New York

I use to have one service turned on for one apartment,and later on my family move in another apartment and get gas and electric and that is all when it started,they start to send me bill for $2985.00 and they allso report me to colection agency,and they come to shut off,but meter numbers did not mach so they fix it by transfering bills to existing one,and this bill is only for couple monts becose i dont want to pay something that is not mine,they continue to send bills.Second i get only electric in comercial space and they bill me for like more than half year for full service (gas and electric),again i try to contact them so many times and they fix every time by transfering money from one bill to another and now is close to $4000.00.What to do.

Emilio
utica, New York
U.S.A.