Stocks and investments aren't liquid cash. They do require 3 months of bank statements but I think the 500k baht or equivalent only needs to show in the final one
I suspect its somewhat lost in translation, the date they gave you is around 180 days and when you'd have to go for an extension. You should have been able to file a 90 day report today
They say 7 working days but that's only if you don't have to supply further information, attend for interview etc. But you do need to remain there until the process completes. The Malaysian consulates appear to be quite strict. And you can only apply online wherever you apply