Unfair policy

I’m not happy with Booking.com policy . I made a booking with booking.Com website as always and realised I made a mistake with the date and when I called them to change it I was charged more of the price that was advertised on their website . I initially cancelled my booking and was told to wait for 7 to 12 days to get my refund back . This is totally not on , hardly no feeling or simphathy for the next person . I mean hardly 30 min after paying , and realising of the mistake .

This needs to b revised as soon as possible