Vodafone — Fake calls and charges added to my account

Address:

10th main jayanagar, 109

Dear sir
I have take Vodafone roaming plan and presently staying in Thailand .
Vodafone bill has come for 5260 rupee claiming that I have received the calls from India but in actual there is only one call which I have received and it's hardly 30 sec .
The calls which are showing are non existent in my mobile .there is something fishy about this case .
We are very clear we have not received these calls and all these calls are both operated calls .