Tata Docomo — generating monthly bill statement improperly

Address:	Bangalore, Karnataka
Website:	www.tatadocomo.com

I had a tata docomo walky (Cdma) postpaid connection with a/c #[protected].
In feb and mar 2018 i had received at least 20-30 nos sms and e-mail mentioning that "tata docomo is going to stop their cdma service on 18th mar.. Customers are being requested to switch to docomo gsm-pre-paid connection or choose any other service provider". I went to indiranager tata docomo center, they told if i get a pre-paid number (Docomo) and set (Gsm), after 18th mar up to 2-3 months the phone calls to the present number (Cdma) will be forwarded to the new pre-paid number. So i booked a pre-paid set. Up to 18th i have visited several times, but they could not provide the set and finally they told they will give me on 18th mar only. But still did not get the set on 18th too. After that i have chosen another service provider. I have paid all the bill amount of feb-mar cycle (Last payment made on 30th march 2018 and cleared all dues till that time). And after that they have sent 2 months bills.. And now harassing like anything through phone calls and e-mails. They have threatened me that they will take legal action. I told them i am not using their service, because you already told you are discontinuing your service they asked me to show cancellation receipt!!
1. My question is, once they announced that they are stopping their service and asked to choose another service provider.. Why i need to send a request for cancellation?
2. Also if they re-start their service.. Why not they take my consent whether i want to continue to avail their service or not?
3. I do not remember how much i paid for the set. Once you stop the service want to get the money refunded to me.
4. Request you to stop harassing me, i do not have any pending amount till the time your regular service was on. All dues clear till 30th march 2018. Transaction id: [protected].
5. As the billing cycle around till 5/6 th of every month, i am supposed to pay only for 13/14 days rental and call charge if it is there.. Not for entire 2 months.. It should be adjusted with the money i paid for the set.