First, you're losing money doing it this way. When you want STEEM for SBD it is better to buy it in the market than convert it. In the market it's close to instantaneous when you choose a "fair" price from the list.
Second. If it doesn't post to your account after the 4th day, you may wish to ask in steemit.chat #help
RE: Er, Where's my Steem gone?! Help appreciated!!