Vodafone Idea — Bill issue

Address:	ahmedabad
Website:	www.myvi.in

Last month vodafone idea
raising my bill in family plan.
regular price of bill is around 1000 Rs.
and this month billed price 2100 Rs.

why i pay extra charges ? of another unknown no. which i never called
from my end.
system says on 7th sep. calling from my family member ISD no...some unknown number

but in my family no one called that type of number
i have proof also in call log same day screenshot from my mobile..
no trustworthy thing..

they blamed me you deleted call from your side.

that's vodafoneindea system errors...or faults we never called this type of number.

and customer care says we are calling you back but i have been waiting for your call for the last 5 days.. no update from vodafoneidea side, worst services..

vodafoneidea name is big but services are very poor..
and also from customer care says we are refund 300-400 rupees
Main Question is
WHY I PAY EXTRA AMOUNT FOR UNKNOWN NO. WHICH I NEVER CALLED