Zoomcar — Inappropriate charges and no customer support

At the end of my trip the driver came hours late for pick up and in the app I am being charged extra for late return. I have tried calling their customer support 5-6 times and they never receives the call. I have been receiving constant mails from zoomcar to pay the outstanding amount however, when I sent a mail, there is no response. I sent the mail regarding clarifying the outstanding amount in which I also mentioned to call me but there has been no response at all.