You hAve 2 choices, 1 being spend more money on someone new, of which you may end up with the same situation as you're in now, or 2....give this guy the chance to get his work right. Now, if he wants money to correct his mistakes, then he's a hack, tell him to f%*k off, and I want his name posted on AZB right here. If he's genuinely trying to do his best work, he'll bear the cost of his mistakes as a learning process, if he needs some advice....tell him to call me.
That right there sounds like an incredibly generous offer of your knowledge.
And good advice for the OP.