I think, "will be postponed again".
The preceding part though is incorrect. You cannot be postponed. Denied - may be.
Your visa can be postponed.
"In most cases, if someone's visa is postponed, there is a good chance it will be postponed again".
A person still cannot be postponed. Only an action can be postponed, since only an action is associated with a specific time.
Even the visa itself cannot be postponed. It is the issuance of the visa, the action that a government must take about that visa, that is postponed.
Therefore: If the issuance of a person's visa is postponed, there is a good chance that it will be postponed again.
But by the same token,
What do you mean by this? "A postponed"? You cannot be postponed or "a postponed". Also what does it have to do with the military status? You have to explain it first.I always says I'm a postponed, is it that right?
"To postpone" is a verb that means "to put off the time of something until later." There is no such noun as "a postponed." You cannot be one, because this word does not exist.
What is postponed here is the start of your military service. However, that is only true if you were given a date for it to start, and that date is then changed to a later date. If you were scheduled to start on Feb. 1, and then you were told you will start on March 1, then the start of your service was postponed. (Informally, you can say that your service was postponed; people will understand that you are talking about its beginning.)
There is also a term that relates specifically to military service: deferment. You can say "I'm deferred" if you do not have a specific date at which your military service will start. In the U.S. when we had military conscription (or "the draft"), one could get a deferment as a university student. After a student graduated, it was possible that he* might be called to serve, but there was no specific date for that and many students were never called at all after they graduated. (Some of them qualified for other types of deferment, such as parenthood or work in defense-related industries. If a man could maintain some sort of deferment until he reached age 26, he was safe from being drafted.)
*Military conscription - the draft - applied only to men.