Bad customer service!!

I made reservations for the rooftop bar for my birthday and was told to book 2 weeks and advance and to pay to secure the booking. After doing all of that and sending proof of payment. 5 days later I am told that they cannot accommodate me at the rooftop bar as they having another event there. How unprofessional of them firstly. After advising that I want my refund, there is no communication what so ever and I have to chase up to find out when I'll be refunded. For a big international business like this I am utterly disappointed and disgusted by your customer service!