Japanese penpal signal

So, he's my japanese penpal, 21y.o. We're chatting everyday. I've known him for 3 months.
A week ago, he asked me to add his facebook. He ask me if i have skype, and want to have video call with me.
But, when he asked me to turn on the skype, i'm on my friends' birthday party, so i decline him. Then, after that he answered 'ok' only.
Yesterday, he called me via LINE. he said that he's having free time. But unfortunately me, i was driving to my friends' birthday party (again), and i asked him if we can talk just a little bit, because i'm driving.
He answered 'good job', and i asked him what does it mean.
He said 'you always go to your friends' bday party'.
Until now, he won't reply my messages.
What should i do?

It was yesterday. Chill out.

To construct the penpal friendship is an extremely difficult and take time. If one side disagree with the other, the friendship corrupts easily.

He thinks you are busy?

Counter-propose a good time to chat.

He sound very clingy and lonely... especially it just a penpal and that is not normal. That his problem, not your. He must be having his personal issue.

i dunno, i think you are giving bad signals

if someone i was talking to was always somehow going to somebody's birthday party literally every time i tried to talk to them, i would think they're lying and just don't want to talk to me

at least in Japan, if you tell the same (or similar) reasons against the same (or similar) offers, it means that you DO NOT want to do that. To prevent such a misunderstanding, we will tell different reasons against the same offers, even if the reasons are the same (or similar).