like i said, that is to be expected out of aftermarket lights especially apc. there is nothing you can do about it. and replacing them was stupid, they are made out of the same mold so its not like the new set is going to fit better.
fit is one of the reasons why people hate them , they are just bad quality with bad design.
you might try to tighten up the bolts that hold em in the hatch area a little more to bring them closer to the body but they still will not fit perfectly. that is the fact of life.
so you can either drive like that, return them and get a pair of j/edm lights or put the stock ones back on (which btw, also have a slight gap).