Contractor headaches, looking for advice with investment property

[Cris Larreo]

Hey guys, 

I recently had an issue with a crack in a bathtub.  I have found someone to come take a look at it and do the fix.  Paid him when he told me work was complete and he sent some pics.  About 6 weeks later, the crack is back and this contractor is completely avoiding me.  Does anyone have any advice on how to get this situation resolved, or experienced a similar thing?  Thanks!