"keisunnate" I guess you meant "Kini sunnatte." ? If yes, it means something like "Never mind." "Don't feel bad about yourself." "Take it easy."

Moshi moshi, Ossu and Konnichiwa means "Hello!". Those are the japanese words that you will use for greetings. Arigatou means "Thank you!" and if you're going to answer "You're welcome." you'll say Dou itashi mashite. Keisunnate? I've never encountered this word before.

mosi mosi

Hi Rashid, my personal suggestion to you is ... earlier you can give up Romaji, faster you will learn Japanese. Try to use a software (or install East Asian Language package on your PC) and start typing Kana and Kanji.... It'll be a more exciting experience for sure. Cheers!!