I believe answer to your query should be

Your time should not be wasted.

Please do Recheck with your Answers.

Active and Passive Voice as well as Indirect and Direct Speech are key components of English Grammar and are found relevant not only to Class 10, Class 12 English, but also for Higher Examinations where youre tested in English/Verbal like GRE, GMAT, IELTS, TOEFL as well as CAT, XAT, Management, Government Services and many other Examinations.

The voice change of the sentence provided is:

You are advised not to waste your time.

Here the rule to change the imperative without the subject is:

You are asked/ordered/ commanded/ advised + to + same imperative

I hope my answer helps. All the very best for your future endeavors!