Still waiting for invoice after 20 days

So i booked a car with Europcar in Sandton for December and the service of this company is getting worse by the day. first the car that was reserved for me was due for service and am not sure what kind of a genius will sign off for a car that is going out for more than 2 weeks that is due for service while on their terms it state if any person drivers a car beyond its service interval will be liable for additional costs. secondly the car was returned on the 2nd January 2018 to date i am without an invoice or a refund of my deposit i have never received a call nor a mail stating any form of delay i tried calling them and well like i said useless services u might as well just don’t call!! i will always regret ever using them.