The Mickey Mouse (and Minnie Mouse of course) Pre-Stamped Postal Card / Postcard set of 2 is sold out at the counters. It is also sold out on eziemall.
The final option is for SODA members to order via SODA order forms:
Ooops, just got news SODA is finished too.
Updated 15 November 2018:
A surprising information, when I asked Philatelic Bureau today, the counter is accepting the SODA order forms including the Pre-Stamped Postal Card set! I guess it is who you ask. Anyway, no harm in sending the order if you missed out.
Shah Alam General Post Office still have the Pre-Stamped Postal Card set. Go quick or the dealers will grab the stocks! Many thanks to Jacqueline (myfdc reader) for sharing this vital information.
sky52200
myfdc 
According to SODA officer, this pre-stamped Postal Card also no more available via SODA as it was fully sold out.
Thanks for this important information!
sky52200
You’re welcome.
This Disney stuff not my cup of the, but i do collect 1 set for my wife. Lol
Shah Alam GPO still have some of this postal card set as at this morning.
Thanks!