Sounds like Luke is doing well. Bit more info required, he hasn't eaten ever or he hasn't eaten at the store? What are you trying to feed him, pinky rats, fuzzy mice, live, pre-killed, F/T, and how much does he weigh? I wouldn't be to concerned if he hasn't eaten by day 14 unless he's starting to lose considerable amounts of weight. If they weren't able to get him to eat at the store the first time around, I'm not sure what good would come of bringing him back their, other than a possible refund I suppose.
Also, it will help the eating process considerable if your husbandry is spot on, two hides, one on the cool side, one on the hot side, correct temperatures etc. An excellent resource is here if you haven't read it already: Care Sheet