iPad sending Mail Problem

Hello, so whenever I send an email to a person, (I send them in Greek Characters), they reply to me saying they can't read the message, and I see the message and it says:

"Original Message:

, .

;

, ."

I compared the original message with the corrupted one, and it's the same, except the Greek Letters are replaced with spaces. It can only recognize commas and dots.

When I send a Mail in Greek to the same E-Mail, the receiver receives the original message with no Problems. The problem only occurs on that specific mail, but when I send a mail from the computer to THAT E-Mail in Greek, he says he can read it perfectly.