Why all the different company names

The plus point was that the car we'd opted for wasn't available so we got a bigger one. Thankfully I know how to drive an Automatic (I'd booked a manual). The list of minus points is, alas, much longer. The phone number on our Rental Confirmation was for a company called Green Motion (which wasn't a name I'd seen on the booking platform or on any of our documentation). The lift from the airport to the office was very prompt and the driver was pleasant but the office is in the back of a Motel/Hostel. I felt very uncomfortable back there. Then the insurance options were presented and the huge deposit required in order to forego the insurance cost. There was no option but to take the high daily insurance cost. The £50 deposit is still sitting as "pending" on my credit card despite being told that it'd be refunded on 9th June (i.e. when I handed back the car). The whole experience has made me feel swindled.