*****ing customer monies from their banks

On 14 January I rented a car from Thrifty car rental at Kingshaka International Airport. I returned the car on 17 January on full tank. On 20 January they took money from my account and upon my telephone enquiry I was advised the debit was for fuel. I was horrified by this as no way in hell it would have been a matter of fuel - I filled up the car at Sasol which is less than 300m from the car returns terminals. I was taken from pillar to post whilst holding on the phone until after 18 minutes when a lady advised the transaction on my account was made in error and that it will take 7 days to refund my money back. It was hard to swallow how they *******ly debited my account and later say I'll have to wait for 7days to get my hard earned money back. The lady called me the next day and advised the refund will no longer be 7 days but in 24hrs which until today it hasn't been refunded. This did not only mess up with my banking but rather the service was shocking to say the least and to even think they haven't refunded my R7000 deposit of 14 January to-date is another dreadful experience for me. I've called then numerous times thereafter following up on this case but no one seems to have a precise solution to my matter.