Tickets display ??? for Cyrillic language

We have an event title partially written in Cyrillic language (Russian). In the confirmation email - the title is written properly, but in the PDF ticket it is displayed with ???? which is ugly for the customers. The same goes to any other description fields in PDF. This needs to be resolved as soon as possible. See attached screen shot.

Hello

Could you please submit a support ticket sending us super user account of your site? We will need to check and find a right PDF font for your language to have these characters displayed properly

Regards,

Tuan