Using a bid-bot is a totally different thing than what I describe here. I have used all bid-bots since the first one - @booster - came out. They all have their flaws and hiccups and it is ALWAYS a gamble from the start. I have no clue what happened with your 0.5 SBD but using such a service is always risky. You can contact @therealwolf on discord and tell him your case and he might be able to refund you.
However, what I describe here is a totally different system where your value is calculated exactly and you get the according value in either an upvote or by seeling your own upvote. That works 100% reliable so far in my experience.