Case sensitive search

Hello Support!
My site is in Greek.
I’ve noticed that search is case sensitive and also requires the right Greek punctuation in order for it to work.
If I remove punctuation and upper case it works fine, but looks very ugly in category sidebar.
Is there a way to fix this?
The site is currently under construction, but I can open it for you if needed.
I find your plugin very good and I am considering to purchase it.

Thank you,
Vana