Canara Bank — refund not get credited in account

I purchased a product on amazon on 15th of this month using my canara bank debit card same was not received and i asked then for refund. As per their confirmation refund was initiated on 19th of this month maximum time frame was 5 days. Still it was not reflected in my account. They had provided the refund reference number 75503729020026351623441. I had contacted customer service number there is no proper response.
Please do the needful.