Hello and welcome to the forum avazhon san !! I hope you stick around and learn even more Japanese !!
bikkuri shita yo, means (depending on contextual setting) I was surprized.
kotaerarenai, means (ditto) I can't answer.
gomenasai, means I'm sorry.
I hope to talk to you later !! There is an area where you can ask questions about Japanese, please do check it out !! MM