Camshaft Phasers?

So recently I have had a rather large repair done on my car. They replaced the timing chain, the head cover gasket and one of the cylinders. This repair cost me $3,500. I do feel like I got a decent deal on this but that being said my car one week later the check engine light has come on. It was really sluggish to start and that was the early symptoms of these other issues. I got it to the shop, and they now tell me that the phasers have to be replaced. My issue with this is why was this not caught the first time. They want $1,500 to do this repair but my issue is that it seems high when I feel like they should have caught this the first time. Now they want me to pay for the motor to be torn apart again. So, my main question is, is this normal for the phasers to go out after. Should it have been caught and should I just pay the $1,500. Also, will this be the end of my issues?