I have never used any of the bacteria in a bottle products, so can not comment on their effectiveness. I have cycled tanks with fish in them and got through it by doing daily 50% water changes and reduced feeding. Even decor out of an established tank can help kick start the cycling process. I would do back to back 50%+ wc immediately to get rid of the high nitrite level. Keep changing water until the nitrate readings come up and the nitrite is 0. As others have suggested it would be easier to return the fish, and cycle the tank completely before introducing more stock.