Overcharged and still no refund

I collected a vehicle on 27 Nov (19:00) and returned on 29 Nov (18:00), an hour before it was due. I should have been charged for 2 days. On 30 November, Petro phoned to ask if I was still using the vehicle. I said no because I returned it the previous day. They had not booked the return into their system.<br> <br> I phoned through and they admitted they had overcharged, but now a month has gone by and still no refund. Imagine if I were to rent a car and only pat for it over a month later. Their administration is poor and *********. There is no reason for a refund to take over a month.