Do you have bio media in your filter? If so, you can still add little more to house more bacteria. I wouldn't put anymore additives in a cycling tank, although two months is way over the cycling process already. Sometimes the problem when cycling is rushing by adding additives, changing water thus prevent the natural cycling process. I think what you're smelling is ammonia, just don't add anymore additives and let the tank be for a few days. I would add more bio media( bio balls) and that will definitely cycle your tank quicker.
If the additives is to detoxify ammonia, it could mean that are no nitrite bacteria because the ammonia is being eliminated before it can process to the next step. You can't stop a cycling tank, you can only stall it by not leaving it alone.