Tata Docomo — Misuse of Tele Calling Guidelines and threatening the customer

Tata Docommo has been calling customers from the non sales number. I have bee receiving calls from [protected] which is a non sales or service number. For my account No[protected]. I have requested for disconnection of account which never happened on time. They continued charging till the limit get exhausted. To adjust the same they have utilized the deposit of Rs 1500 deposit to them. Now they are asking to refund the router else they will charge me 4500 additional which is completely cheating on top of it they are threatening to sent the legal notice.