I did there too but no response yet.
I know it's not appropriate time, but maybe others will find it helpful,
for viewing bangla properly in illustrator / Photoshop.
go to menu EDIT > PREFERENCES > TYPE
you will see there is a 'Language Options' or 'Choose text Engine Options' (It varies from illustrator / Photoshop version you use)
check 'Show Indic Options' / 'Middle Eastern and South Asian'
Restart your illustrator (must).
Hope it will work.