Can theories be wrong?

Yes, theories can be totally wrong!!!

Right now we have the theory of Dark Matter & Dark Energy. Is it right?? We're not sure. It seems so.

What is a modified version of gravity comes out that does a better job and can be experimentally proved?? Then we throw out other theories.

Theories are a progress, not a destination.

The closest thing I know of to a theory that has been completely overturned in the past century or so is Lord Kelvin's theory that the Sun was powered by gravitational collapse and chemical reactions. His early calculations gave 400 million years. Over his career he steadily revised this downwards to as little as 20 to 40 million years and probably closer to 20 million. Other scientists of the time came up with ages of 50 million years or so.

Geologists including Charles Darwin strenuously disagreed.

Kelvin's theory worried Darwin since it left insufficient time for his evolutionary theory to work and Darwin began to look seriously at Lamarck's ideas.

About 15 years after Darwin died, the discovery of the heat released by radioactive decay meant there was an alternative source and eventually it has been found that the Earth is older than even Darwin expected.

Some earlier "theories" were little more than speculation or hypotheses with next to nothing to back them up. They might have been wrong but they were not really theories in the sense of being backed by multiple pieces of evidence.

Sure, theories can be wrong?

But they can also be right and verified in spades.

The theory of evolution, for example, which has a massive amount of evidence for it, the lies and deceit of the promoters of creationism notwithstanding.

Other theories have been verified as well; Einstein's theory of relativity, for example. The GPS system must even take relativity into account or it would not be as accurate as it is.

Yes, of course, but that doesn't discredit science, which I'm sure is your goal here as a Creationist. Science learns and grows as more and more experimental and observational evidence is collected on a subject. Religious fundamentalists, by comparison, blindly cling to what they believe are scriptural teachings no matter how absurd, such as Earth being 6000 years old, and then only rarely change their minds no matter how much physical evidence is arrayed against them. Science adapts.

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Consider the cold fusion theory. Out the Russian 'polywater' hypothesis of the 60's. Now consider the geocentric solar system. Or the Greeks belief that the eye emits rays that illuminate the object it sees.

There are tons of them.

yes, theories by their nature are more often then not incomplete. Even Einstein's Theory of General Relativity by his own words was incomplete.

All the time. The problem is more with the word "theory" and the inaccuracy of the English language than the scientific method though. The word "theory" can mean both an untested hypothesis AND a well proven one.

The rightness of a theory is highly desirable, but the usefulness of it is more important.

yes they can be wrong