Hey my friend I've had the same issue. I traded Steem (or SBD) for BTS and now There's no way to withdraw those BTS, about $10 worth, or 68 BTS.
I tried everything...I even got lots of good feedback from BlockTrades and Bitshares. I thought my BlockTrades wallet where I carried out the transaction was my BTS address but apparently not. I created other BTS wallets. It still can't retrieve BTS from BlockTrades.
They did confirm my trade and showed me the blockchain data, but where is it????
Only $10, so I gave up. If BTS skyrockets, I'll try again!