Looking on the internet deeply has found these results:

Won't be postponed is the most popular phrase on the web.

Wouldn't be postponed 1284,000 results on the web	Won't be postponed 1882,000 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
The wedding has to be postponed. I fear this ritual must be postponed I'll inform the Valtese delegation that the conference has to be postponed. I can't let their wedding be postponed again. This time the necessary debates and the necessary action must not be postponed. Perhaps this discussion should be postponed until the king's return. Your wedding will be postponed a day at most. I think the discussion of this text can be postponed till tomorrow.	Your wedding will be postponed a day at most. This time the necessary debates and the necessary action must not be postponed. I think the discussion of this text can be postponed till tomorrow. I fear this ritual must be postponed Perhaps this discussion should be postponed until the king's return. The wedding has to be postponed. I'll inform the Valtese delegation that the conference has to be postponed. I can't let their wedding be postponed again.

Wouldn't be postponed

1284,000 results on the web

Won't be postponed

1882,000 results on the web

More popular!

The wedding has to be postponed.
I fear this ritual must be postponed
I'll inform the Valtese delegation that the conference has to be postponed.
I can't let their wedding be postponed again.
This time the necessary debates and the necessary action must not be postponed.
Perhaps this discussion should be postponed until the king's return.
Your wedding will be postponed a day at most.
I think the discussion of this text can be postponed till tomorrow.

Your wedding will be postponed a day at most.
This time the necessary debates and the necessary action must not be postponed.
I think the discussion of this text can be postponed till tomorrow.
I fear this ritual must be postponed
Perhaps this discussion should be postponed until the king's return.
The wedding has to be postponed.
I'll inform the Valtese delegation that the conference has to be postponed.
I can't let their wedding be postponed again.