Renault parts scarce and difficult to get

I'm a bit frustrated.... My car has gone in on thev5/09/2018 to be fixed, they advised that the tailgate is on back order it will take about 20 days, and till today there is no ETA on the part..... Now I find that very nerve-wracking that the parts need to take that long to arrive... I am 38 days without my vehicle, because the place that's fixing my car is waiting on the tailgate since the 5/9/2018. Please advise how to get the part asap.