I get confused. blockchain.info is only for storing bitcoin. How could you send dollar from that? You even claim sent dollar to your BETCOIN deposit address. BETCOIN deposit address? How could betcoin receive dollar? Betcoin should be totally different coins. How coulld it receive bitcoin? Can you make it clear?
I expect that he means he sent $20 worth of Bitcoin, rather than sending $20 over the blockchain.
Try contacting Blockchain support if it's an inconvenience. They can probably help you out.