我有一个月没收到我澳大利亚的笔友的来信了.用英文怎么说

I have not received any letter from my penpal in australia for a month.

I haven't received a letter from my pen-friend in Australia for a month.

I haven't heard from my panpal in Australia for already a month.

I have not receiced any letter from my Australia pen friend for one month.

I have not heard from my pen friend in Australia for one month.
or
I have not received any letters from my pen friend in Australia for one month.