Refund of wrong and void transactions not processed

I had made a purchase of INR 7134/- at Metro Shoes store at Viviana Mall in Thane. Due to one order being cancelled, the entire 7134/- amount was void by the storeperson assuring that it will automatically be refunded in my account. The final bill amount of INR 5289/- was separately swiped on my debit card dueing which the card machine hanged. Money again got debited from my account. On detailed investigation, it was confirmed by metro team that INR 5289/- had been credited in excess in their account. The transaction date was 11-Feb-15 and it has been more than 3 weeks now but there is no sign of any refund. Whenever I call up the store, they just keep asking for more time. It seems they donot take customer’s money as their own and do not care to solve customers problems on priority basis. I wish to find a way to sue the store owner and take back the total money of INR 5289/- and INR 7134/- which had been wrongly debited from my account. Kindly help me with the same.