Poor/No Service from Mercedes-Benz SA

Mercedes - Benz is advertising that they are selling after sale service and a lifestyle. Sadly my experience has been dismal. I purchased a new C205 Mercedes, last year April and unfortunately was driven into by a truck 18 June 2019. The car had to be towed to the panel beaters and was reported to have R140,000.00 damage to the rear of the car. The problem began on the 24 June 2019 when the parts were no available, a new bootlid could not be found., neither in South Africa or Germany. So a month later 17 July 2019 the bootlid should have finally been delivered to the panel beaters. I have had to privately finance 1 month rental car fees. With still another month to fund, since my car will not be ready for at least another month. I feel that the least Mercedes Benz SA can do, is apologise and supply me with a courtesy car for this month as I have sat waiting for parts for the last month. I have tried repeatedly to get service from the Mercedes Benz SA customer services department, I lodged a complaint 12 July 2019 case no ***. They initially tried to fob the responsibility off on the insurance company and when queried, nothing more has been done and no further contact received even after I have attempted to contact them. I have left a message 17 July 2019 for the Customer services manager to call me back and I am still waiting. So now, no lifestyle, no service and no Merc. Is this acceptable?