Another way to get legitimate vitatalalay is go to the netherlands website and order and ship it to a warehouse where your freight forwarder can ship it to singapore, i do this for some america and china goods like toothpaste and stuff but i swear that their website is the most user unfriendly thing i had to navigate, even with the amount of studies they posted
There are studies on which mattress material deters dust mites feces, in 2 particular ones i saw, spring >polyurethane foam, coconut husk> polyurethane foam but i doubt you want to sleep on coconut husk as it has its own set of problems