MTS / Sistema Shyam TeleServices [SSTL] — wifi data card

I have made my last bill payment for my wifi data card on and have registered a complaint on customer care through my alternate mobile number since my registered mobile number have been lost. I had registered the complaint that my wifi device have dead so kindly disconnect my connection since when i had made last payment, many times i contacted customer care regarding this issue but no response, buy they generating the bill monthly without fail. I need to know why should i pay for the dead wifi which was not in use for past 3 months. When made the complaint in customer care they told the they will take my complaint and clear my issue but still now you sending the bills and legal notice. How could i continue in this network and what for this customer care working for???