Unrealistic turn around times and lack of communication and courtesy car

I sent my Renault Megane GT 1.6T for brake pads replacement at Renault Cresta - Motus on the 19th of May.

I was told that I will get back my car the same day since I arrived early, But I was called at 4pm with them informing me that they found an error in my car related to some pipe in the engine, I have never experienced any problem like this with my car.

They said I can not drive my car with this issue and they do not have replacement parts they have to order them from France and it takes 10 days. I agreed for them to order the part, but they said I will not be able to drive my car.

They do not call me for feedback, I have to keep on calling them, When I called today (06 June) 18 days later. I am being informed that my part will only arrive here on the 23rd of June.

Mind you they still have my car there, soo basically I will not be driving my car for 35 DAYS, and I am currently paying for it.

Remember there was no error light or anything on my car, I drove it there to get brakepads changed but now, they are saying my car is not drivable for 35 Days.

When I call customer care, their line is not working.

The only courtesy car they are offering me is a Renault KWID, even if my car is a Megane GT 1.6T. I don't understand