Don't matter and SAGAWA KYU BIN

I like Akon's song.
"Sorry Blame Me", "I Wanna Love You" and "Don't Matter"...
I feel his song is fresh.
So I like to listen his song.
Yesterday My friend said to me "I can hear "Don't matter" as if he is singing in Japanese."
She also said that I think lyrics to this song of "Cause I got you babe" sound like nothing but as "Sagawa Kyu Bin".



Sagawa Kyu Bin(佐川急便) is a name of the most famous transport company in Japan.
Though I can just hear his song normally in English, I can't catch the lyrics in English.
I just hear the part there only in Japanese.

Have you ever had such experience?