Found out a solution. Posting it here if someone finds it useful...

I dint wanted table because, I wanted to send a simple mail not html mail..

solution:
go to yourdomain/admin/structure/views/view/commerce_line_item_table/edit/default

change it from table to any list you want

now when you use Line items (with underscore) : [commerce-order:commerce_line_items] in your email

you will get the desired list of ordered items