TATA Indicom/walky — getting wrong bill

Respected,
Sir
I m using this walky atleast two years and it is zero rental for three years and its credit limit is 3000
but in december i changed walky because old walky is creating problem in december my bill was increasing contnue 500 a day it was on cloning and someone using this number also.
i complained it 6 or 7 times in customer care he told me it is on cloning and u will get ur correct bill.after cutting ur cloning amount but i got Rs 10000 as a bill and my credit limit increased 10000.
please do something
thanks