This is week 20 and the supplier did not deliver the material till now.

Do all the given sentences are correct and describe the supplier's failure?

1. You are supposed to deliver the material by week 12. (You have failed in your duty)
2. The materials were supposed to be delivered by week 12.(in a passive statement)
3. You were to have delivered the material by week 12(You should have delivered but not)
4. The material were to have been delivered by week 12.(in a passive statement)

Kindly clarify me.

It seems to me that #1 could still be speaking of a future event. If the 'are' were 'were' it would be more clearly a failed duty.

#4 should read 'materials', not 'material'.

Otherwise, they seem to say what you think they mean.
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What is difference between 1-2 & 3-4?

I don't see any real difference in meaning. The second pair are more depersonalized (because 'material', not 'you' is the subject) and more formal (because of the 'be to' verb form), and so are more suitable for the business situation.