Vodafone India — Balance in my prepaid cards deducted automatically

Address:	Mumbai City, Maharashtra
Website:	www.vodafone.in

Since past 1 year, after every successful recharge on my vodafone card, there is a balance deduct of random amounts eg. Rs. 28, Rs. 40, Rs, 60. Whevever I call customer care for rectifying the issue, they end up saying this cannot be done as there was an international call received but I never got an international call at any point of time. Also, they never give any details of the call received. Please help me solve this issue and guide me for further steps to be taken for the solution.