State Bank Of India [SBI] — refund amount not credited in my bank account (transaction dispute)

I had purchased a product with amazon which i later returned.
As per amazon the refund request was accepted and refund reference number is[protected]. I did not get any refund in my account even after 20 days. On contacting amazon they say its the bank problem and on contacting the bank they say its "gateway problem"with amazon. Please help me out with this.