HDFC Bank — Credit card EMI started without knowledge

On first December I've purchased one item from amazon by credit card EMI.But after receiving it was returned due to faulty item.and on 5th of December same amount was returned to credit card.but when bill came emi started and we didn't notice till February because emi was credited to credit card .when i inquired about it nobody wants to solve it but wanted to pass this issue to one-another. Needed to solve it very urgent because i;ve used somebody else's card and they notified me about this.Pls Solve this issue.

Total Amount 9596/-

Deducted as -3156, 3198, 3241.12 with emi charge .