Amazon — refund not transferred into my bank account

I ordered 2 watches from amazon on 15/12/18 but i cancelled that order on same date. Refund is transferred into my account on 21/12/18 but it is not shown on my bank account. Transaction id is 784426. I had contacted to bank customer care they said refund is not transferred into your account. I also contacted to amazon customer care service but they said that refund is transferred into your account on 21/12/18.