Disappointing service/service department unreacheable

I'm livid, I phoned renault clearwater on the 30th November to book my car in for a service and they gave me the 2nd December date, I accepted the date and on the 2nd I had emergency that I needed to take of and I phoned them to cancel the booking and set up a new date, they did not answer their calls as per the norm, I then tried Northcliff on the 9th December and they told me someone will revert and they took my contacts, today its the 11th still no response I then gave them a ring again and I failed to get through the service department 3 times. So I want renault clearwater to fix this mess as I am traveling on the 18th to Mpumalanga and I can't travel with that car unserviced they told me they fully booked till the 22nd December, that's unacceptable, I will not take it!!!!