Mercedes Umhlanga and Mercedes SA pathetic aftercare customer service

I am disgusted with Mercedes Benz SA in handling my situation with mercedes benz umhlanga dealership ,I have my vehicle in for repairs for over 4 months with no response or assistance from either party and I have a motor plan I have requested for a Courtesy car until the repairs are complete but mercedes Umhlanga has insisted that in order to get a courtesy car i got to take personal insurance on the courtesy car ,After contacting various Insurance companies which all had the same response they do not give out insurance on other peoples vehicles and mercedes usually already have insurance on they courtesy cars. I have lost income as my vehicle is in repairs and unable to move around before the lockdown. Mercedes SA says they cannot do much its the dealership i got to deal with unless it has something to do with a international part. I feel the service that should have been carried out by both these institutes are pathetic because other than not replying to my emails for information or calls they have just ignored me ,My next step is taking this legally and i have contacted my banks to ensure they take this up both with mercedes because i cannot be paying for a vehicle that i do not have