Why i have not received my money back

I purchased a book online from your site on net that is 2 months back with cost of $90, the book was about VPN i used my Techrepublic User Id and my credit card but i return the book on the next day when i found that book was uselees to me or i donot like the contents. why why my money till now has not come back to my credit card account. who is responsible for it. i want to know about my money status. can any one give me this info. ??

thanks

my login id sambitnanda@yahoo.com

sambit