TS, i am sympathetic to your situation but my sincere advise is perhaps to attend Bahasa Malaysia speaking courses

as long as you want to hold a Malaysian Ic/Passport and don't speak the language, you're going to face such problems and worse in future

and just to digfrss, if the situation was a USA citizen wanting to renew the passport but can't speak English cos he was educated in Mexico as a child and grew up his adulthood in Mexico, the USA citizen would face similar situations as you or worse

not judging but merely suggesting a long term solution for you and your child

and the immigration officer was just following the rules when she asked for the detail document such as divorce papers

they need to be sure everything is in order cos a lapse could have happened when the passport was issued so each renewal must also follow the protocol

you're a good man to take care of a child that is not biological related to you