Wait... Let me guess this straight.... You're worried because you haven't seen the Dubias eat? Lol... They are roaches, very hardy ones at that. Just put food in and they will eat eventually.
What are you feeding them? A good dry gut load (bug burger, etc.) with fruits and veggies is preferable. There's a lot of info on dubias here and on the web. Just do a search and read till your eyes hurt.
Do you have them on heat? What are you keeping them in? Bug burger usually doesn't go over well with my bugs, in fact most commercial dry gutloads didn't, I ended up making my own, which I've modified to their tastes... maybe I just spoil my little roaches <3 Anyway, they should've eaten at least a little bit in the past two days... Do you mean actually physically see them eat? or just none of them are eating but those two? Usually roaches will scatter when you open the container unless they are actively in the process of eating something they are obsessed with at the time >.>
Don't feed dry cat or dog food, it can cause gout in chameleons when they are eaten, and it has a LOT of additives that chameleons don't need and are bad for them. Dry cat food has added taurine in it, which chameleons don't need and vitamins that are added to cat specifics.