Spotify doesn't seem to have any service/script to do this.
A service called Soundiiz is claiming to do the job but it requires a Saavn email/password combination to connect to Saavn. I use Facebook's login service to log into Saavn and there doesn't seem to be a method to generate a username/password. When I try to click on 'forgot password', Saavn says that my email (that is registered with FB and is visible in the Saavn account settings) is invalid/incorrect.
I'm a paying Spotify customer, so really need to move everything there.
Really frustrated by this. Please let me know if anyone has any suggestions.