Stop harassing me, MTS!

Here is my worst experience with any internet provider!  I was having an excellent 4G internet connection with Airtel (which I still continue to have).  My only issue was that I had to pay a quite hefty Rs. 2300 per month for that connection.  So, wanted to try MTS.  They promised me a 3Mbps to 10Mbps connection and said that I have to get the connection activated to try it and that there is no demo option.  I specifically asked them what if I don't get proper speed at my area.  I was told that I can return the data card and that the money I paid for the data card (Rs. 1000) would be refunded.  The data the connection got activated, I saw that the speed I got was just 200kbps - 500kbps, instead of the minimum 3Mbps promised.  This was the speed I got at prime areas in Bangalore, such as HSR Layout (my office area), and Basavanagudi (my home area).  I raised a ticket with them just the next day.  They took a week to resolve the ticket and finally the issue was not solved.  I raised a request to cancel the connection and they took another week to cancel the connection.  Since then, I have been trying to get the refund for the Rs. 1000 I had paid for the data card, but not yet got.  And over that, MTS has sent me a bill of Rs. 599 for the period the connection was active.  Why should I pay for a connection, with which I got much below the minimum speed they promised?  Apart from sending me a bill, these people have been harassing me by calling daily for the bill payment.  This is an open letter to MTS.  Stop harassing me by calling daily.   And give me my refund of Rs. 1000 for your data card and take back your useless data card.