Reliance Jio Infocomm — unable to make the last payment for a terminated no

I terminated my jio postpaid no a couple of months ago but again a bill was generated. I tried going online and to the store for payment and was unable to process my request as the number is not available anymore. Customer care is unable to help me. I finally got a demand notice too for payment. I wrote to their collection team but they bluntly said i need to pay via cheque. But to whom and where? No details mentioned. I have lost peace of mind to pay a meagre amount. It's really torture.