Zoomin India — Refuelling Charges

We did book zoomcar, And paid all the amount completely by that day itself, till yesterday there are no dues, no charges, but now its showing outstanding charges 1700/- saying "Refuelling Charges" First of all the car was dirty and i wanted to change my car, so i went through customer support, they said, we cant change it now, and when my trip started there was no fuel at all, so i did pay extra charges for fuel and fastag was not working too, i paid for that too, but they didn't give me fastag ticket, i left 30% of fuel while dropoff and i applied for my refund, now its showing im due to them, Where did these charges come from all of a sudden, kindly check and resolve the issue @zoomin