Unprofessional business practice

My colleagues and I booked a cruise for April with them. There was a change made to the cabin we booked under the guise that it’ll be free since it was a special. To our surprise we got last minute email notifying us that our booking is short of R2400 when we were trying to purchase vouchers for drinks and data. Since Tuesday we’re trying to get in touch with them to sort this out since the invoices we have do not correlate with this new amount they’re charging us. They’re being unhelpful. They hang up calls n answer questions vague when they pick up. Highly unprofessional