YOU SAID:

I lost my phone yesterday.

INTO JAPANESE

自分の携帯電話をなくしました。

BACK INTO ENGLISH

I lost my phone.

INTO JAPANESE

携帯を失くした

BACK INTO ENGLISH

It's lost cell phone

INTO JAPANESE

それは携帯電話を失ってしまった

BACK INTO ENGLISH

It has lost cell phone

INTO JAPANESE

それは携帯電話を失ってしまった

BACK INTO ENGLISH

It has lost cell phone