Vodafone India — unable to port my postpaid connections to prepaid

Address:

New Delhi, Delhi, 110042

I had 3 airtel postpaid numbers which i previously ported into vodafone a few months ago, but there was a condition to get in to the vodafone that i have to take postpaid connections.
And i agreed to the condition, they were so greedy and one of their executive came to my office directly to take all documents and complete the formalities and handed over the new sim to me and they were so in a hurry that they couldn't even wait for me to be free from my work.

Now, i am fed up with vodafone postpaid as they are charging excessive amount while they are already offering almost same features in prepaid connections, so i decided to quit in postpaid and have my connections in prepaid with same network provider.

I visited the vodafone store in tri nagar, delhi few days back, i told them my concern and they told me to go & visit some other store as they can't change any postpaid connection to prepaid. And this is the same store where they are changing the prepaid connections to postpaid.

Why are they not changing my postpaid numbers to the prepaid? Or they are just intended to complete their targets even if they have to compromise on the services. And as far as i can see the image, losing the postpaid users can downgrade the position of company.