Is it non-grammatical / incorrect to say:

• I just received a call from my friend.
• I just got your email.
• I just read your email.
• I just came from a store.

Compared to:

• I have just received a call from my friend.
• I have just got your email.
• I have just read your email.
• I have just came from a store.

I looked this up as well before asking the question and learned that "have just" usage is often a British English usage. However, I am not completely sure if it is okay to omit the 'have' or not in American usage or, it is incorrect.