Internet company did not send paper bill as decided & now harrasing me

I had a internet connection of this company purchased by their agent. I had clear stated that at time of purchase if i did not receive paper bill than no payment since I have to claim that amount from my office. Till 1 year all was going good & Suddenly they stop sending paper bills & i stopped making payment this happen for three month. Then there executive visited at my house for payment than i told him my problem. I guaranteed me this will not happen again, Please make payment this time. So i made three month payment which i was not able to claim since period of that bill passed. After than again same happen no paper bill for two month. Than i said to there executive that i will not pay this bill. Now they are calling me regularly & harassing me for payment & saying they will file case against me. I wrote to their appellate authority, No proper solution was provided they said you just pay the bill. Why should i pay from my pocket for there issue for not sending bill.