AccountKiller
From their FAQ (http://site4.way2sms.com/content/privacypolicy.html)
To have your account removed, send an email to support@way2sms.com. You'll receive a 4 digit unique number on your registered mobile phone. You can use this to delete your account.
It's not entirely clear for us where this 4 digit number can be used because we do not have access to an Indian mobile phone. Perhaps you can help us out? Leave us a comment!
Publicly visible text/images often aren't properly deleted even when you succeed in deleting an account. Try editing or deleting them manually before deleting the account itself. If you're unsure what happens to your tracks: this can be found mostly in the Terms of Service/Privacy Policy; otherwise you can always contact Way2sms and ask personally. By the way, deletion requests don't necessarily mean your data will actually be deleted (e.g. due to legal obligations).
If you signed up for Way2sms using a third-party login such as Facebook or Twitter, you probably want to revoke all access from Way2sms. Click the icon below to find out how.