Do SW update @ Nokia Care Center to change the language
Yes , I know what happened , you tried SW over the air , you can get your languge back you need to be in the phone by going to the near Nokia care point and they will do SW update for you for free if as i know if you covered by warranty but don't forget to ask them that you need SW with the languge you want .
It seems the phone was not intended for Sale in your Region. The Persian language was not a part of the Firmware but the retailer added the language later on for his benefits. You need to go to Nokia Care and get the language pack installed..but be warned that any future Firmware Update / Re-install will put you in the same condition again, where the language will need a re-install thru' Nokia care...