very disappointed

Uber is delivering a very poor service. Duplicate charges are been deducted for bank cards, even though the fare tip / price / has been paid. Additional costs and charges are added to the same trip taken. They refuse to refund extra charges. A whole "process" has to be followed in order to get one's refund back. They are slow to respond when emailing. No trip will be accepted by any driver if there is insufficient funds via bank card for the trip. Question: So why after paying via bank card for a trip are they still requesting extra funds or charges for the same trip. Disappointed is an understatement