Ola Post Paid — The payments made in cash for my Ola rides are converted as Ola post paid paymentsThe rides

I have been a customer for Oa cabs for so may years and i never used Ola post paid. During my last four rides i paid in cash to the cabbie and after the rides i'm getting Ola post paid payment message, i had raised so many complaint with Ola and it was not resolved. Even one of those payments was by g pay to the driver concerned.
There is no proper human support from Ola App and all are automated calls.
Lately im receiving threatening messages and calls from ola recovery and by messags which is irritating. Just for a sum of Rs.1106 i am being annoyed by Ola. I happen to speak to some of my friends having same issue. Is this kind or fraud or scam.