Amazon India — payment refund not received

I ordered photron p10 wireless bluetooth speaker on 19 th jan 2019. Than i found a better deal on amazon so i cancelled this one. I suppose to receive my refund back in 2-5 business days. But i haven't received my money yet. I am continuously trying to contact to them but i haven't get any convencing answer from them. I also contect to bank they also just saying that they haven't received any refund. Please try to help me and please help me to get out of these. Order amount is rs 649.