Greek often has instances where multiple spellings are used (e.g. αυγό/αβγό, τραίνο/τρένο, μοτοσυκλέτα/μοτοσικλέτα) -- perhaps a little like "colour/color" or "realise/realize" in English.
I had a look in the incubator and your spelling should be accepted in English-to-Greek translation exercises.
Earlier, when a foreign word was adopted in greek, it was written in a way similar as possible to its initial spelling ex: Shakespeare to Σαίξπηαρ or Σαίξπηρ. Now they write it the simplest way, that is Σέξπιρ. Apparently the «y» of «cycle» of «motorcycle» («ειρήσθω εν παρόδω», which means by the way or «μιά που το΄φερε η κουβέντα», «cycle» derives from «κύκλος» and from here comes this annoying «υ» again) was rendered to «υ» but not anymore, now all the foreign languages /i/sounds, either we like it or not, are written with «ι».
That is also correct and accepted. If it wasn't accepted you should first make a Report then comment here.
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.