URSAY, please please help

I made a deposit from bitstamp, using the bitinstant option. I went to walmart and made a payment to "wallet address". I used the address from my "wallet qt" the one shown under receive coins.

My browser didn't show the option in the drop down box for pay to bitstamp. that is why I chose that option.

so frustrated. what info do you need from me, can you please help