Returning to the registration process will help us explain this. We credited your Exotel account with Rs. 1000 when you signed up, which you can use to test out our system.
We requested an Exophone from you to utilise for your testing when you signed up.
For testing purposes, we also invited you to add a co-worker.
These two things each come with a daily rental. The daily lease costs Rs. 75. Your initial credits will also be reduced by the cost of this rental. You have used up all of your credit because of this.