HDFC Bank — one assist membership fee charged without authorisation

Address: 380005

I had applied for hdfc credit card which is duelt received... How ever upon checking my back credit card statement i noticed that i have been charged for one assist membership fee... I haven't raised request for one assist membership nor did i have authorised the bank for the same... Means the membership was charged without my consent... Despite of calling customer care several times no one picks up calls in the customer care center... There fire the issue hasn't been solved yet... I want my refund back and want an answer from bank how can they charge for a service without the consent of the customers

Card ending with:4176