~ "what goes around comes around" is an idiomatic expression.

~ usually with such translations, you either come up with a corresponding malay idiom or you transliterate the sense.

~ an equivalent in malay idiom is probably "ada ubi, ada batas. ada budi ada balas."

~ however in this context, it would be more suitable to just transliterate the sense of "reciprocity" i.e. of "every action has a reaction.