YOU SAID:

two left shoes just doesn't work

INTO JAPANESE

左の靴が2つ働かない

BACK INTO ENGLISH

Two left shoes don't work.

INTO JAPANESE

左の靴が2本も効かない。

BACK INTO ENGLISH

Two of the shoes on the left don't work.

INTO JAPANESE

左側の靴のうち2本は効かない。

BACK INTO ENGLISH

Two of the shoes on the left don't work.