If your tank with plants and growing well. pump or filter out for 24 hours will be fine for them. Unless your tank overload of them. Mostly the bigger shrimp will die first. My filter was out for 3 days...just few bigger shrimp died only. The rest are ok.

Suspecting this...
2) Monday, my maid spray insecticide in her room. Outside her room directly is the aquarium.

Insecticide is very poisoning to shrimp. And you change water for 5% every 2 hours for 4 times. by using tap water or old water from other fish tank or the tangki water? As you knw, they are very sensitive to water change also.

If me, i will do 30% water change 2 times within 4 hours. So, part is yr maid mistake and part is yours.