When you say "some" how many fishes did you add? NH3 is toxic to fish, I know people use fish to cycle their tank, and it has worked in the past, I personally don't like that idea. I feel like it's cruel to the fish. Since you said some, I am assuming you added more than 2 fishes. I don't know how many of these fishes are going to survive. Plus, with fish added to your tank, your NH3 will rise due to uneaten food and fish waste. Depending on the type of fishes you added, it won't surprise me if you lose some of your fishes. I like fishless cycling. If I were you, I'd return these fishes.
Plus, since your tank hasn't finished cycling adding fishes too fast will also cause algae bloom. I would add fishes slowly over time. No need to stock up the tank in one go. This hobby takes a lot of patience. Cycling alone can take somewhere between 3 to 6 weeks or even longer in some cases. You are responsible for any life you acquire, so making sure these fishes survive should be your first goal. I posted the link where it explains how the cycling process works. Please read through that thread. Finish your cycling before adding fishes would be my suggestion.