Very bad service

I booked and paid for a Holiday package to Zanzibar, only for Mango to come back to me and say they had a technical problem on their website and the prices at my checkout was not correct. They refuse to keep the booking and insists on a refund. It is not the customer's fault that they have the wrong prices on their website. It is false advertising and they are misleading the customer. Please don't book with them.