In December I hired a car through Tempest Car Hire

In December I hired a car through Tempest Car Hire. They took a holding deposit and instead of taking R7600, they took R76000. They were made aware of this and I was told they would refund me straight away. We received a message from our bank that the amount was declined. We phoned our bank to check this and we were informed that Tempest is not crediting our account, but rather trying to debit our account. We have been into the branch and still nothing. We are now back in the UK and when it reached 7 working days, they again tried to debit the amount instead of crediting it. I will not let this one go till I have my money back with the interest that I was charged by my bank due to their error