RBL Bank — bank not refunding my money

On 30th September 2019, Mistakenly I processed my credit card payment twice of Rs. 19000 each. When I called their customer service to refund one of the amount, they said that they will deduct the already done transactions without even generation of the bill and refund the rest of the amount without my agreement. But till date I've not received any refund. Even their all levels of customer care and escalation people have stopped responding.