Ola Cabs / Ani Technologies — Bill paid in cash, post paid bill generated

I had travelled on Ola cab to Hybd airport on 19/09/2021. CRN [protected].
I selected the option for cash payment and in the end of the journey, I paid cash to the driver. Later, I noticed that, the billing had got converted to postpaid and hence I reported a concern in their portal (Reference no: 3678428) on the same day. I also did as per their reply mail to my concern.
But on 03/11/21 Ola generated a bill for settlement and mailed me to settle the bill. I again raised a concern (ID: 3721640) and after that I have had numerous email & telephonic conversations with their executives regarding the same. But the issue remains unresolved till date.
On 10/01/2021, I got a WhatsApp message from them stating that, they will send me a legal notice, if the amount is not paid. This is really like harassing me.
I request you to look into the matter and resolve at the earliest.