HOw is one supposed to complete the Level

You have to prevent that from happening @Adnaw . I did pass this level recently without much problem, so I think you must have been unlucky. Perhaps you played too many and too strong boosters early on in this level. The blockers need to be removed one by one, so both dragons will drop down the right channel. Try to avoid using a party popper or a two colour bomb combo. I had a go and did indeed manage to recreate your problem using a Party popper. The first dragon went down the right way but the second, as it followed right behind, dropped down the wrong way.

So I would suggest to yes, use starting boosters as this level is difficult, but beware to remove those bockers one by one and not all at once. Good luck!