That would mean something a bit different: "She does not want the shirt."
The version with the definite article (the/το) implies that you have already talked about a specific shirt before, and the listener knows which one you mean. Then in this sentence you say that she does not want this particular shirt which is known to the listener.
But with the indefinite article (a/ένα), you are not speaking about any specific shirt. That sentence says that she does not any shirt at all.
Well, actually you're right. Full words, as well as contractions, are always accepted and they are in this case as well. In fact we include both in the accepted translations.
So, that means you had a mistake. Now when that happens ... as indicated by Mizinamo you need to show us the sentence.
We moderators cannot see your sentence therefore before you posted your comment here you should have made a REPORT. / Here's how to report.
Go to the bottom of the exercise page where you'll see REPORT Click on that:
Then choose what you want to REPORT: (You'll see these to choose from.) -The audio does not sound correct. -The dictionary hints on hover are wrong or missing. -The Greek sentence is unnatural or has an error.
-The "Correct solution" is unnatural or has an error.
-My answer should be accepted. This is the one you should click on if your translation was not accepted.
After choosing the REPORT you want to make you should post on the comment page.