YOU SAID:

My friend is terrible at answering my Facebook messages.

INTO JAPANESE

私の友人は私のFacebookのメッセージに答えるのがひどい。

BACK INTO ENGLISH

My friend is terrible to answer my Facebook message.

INTO JAPANESE

私の友人は私のFacebookメッセージに答えるのがひどいです。

BACK INTO ENGLISH

My friend is terrible to answer my Facebook message.