they're legit..don't worry

example:
item A from yahoo auction japan
price item A 2000JPY buy it now
sendico fee flat rate 500JPY
usually need to pay that price 1st

shipping from seller to sendico (in toyama) 500JPY (takes a few days)
after arrival, they'll notify via email
you can choose extra bubble wrap, content checking, consolidate etc (at a fee)
then you choose shipping EMS/SAL..japan to malaysia choose EMS better
they give total and then you pay balance (domestic and international shipping, also extra service if have)
then they email back tracking number

hope this helps