Month 4 with my vehicle and no estimated time of completion yet

I sent my AMG in to Mercedes Sandton early December, there was an issue with the Prop shaft and they are ordering a new one. It has now heading to month 4 that I have not seen my vehicle. All I am told is there was a system migration and that they cannot track exactly where this part is in transit and they cannot tell me anything further and I will have to wait…. 3 months down! I do understand a system change however there has to be a way to manually intervene to find out where the part is eg. Call the Part supplier? Surely it is not good enough to just tell customers you know nothing. My problem has already been 3 months, this could be what?.... 6 months/ 1 Year? I do appreciate the VW that you have rented for me (which I am also paying adhoc monthly rental fees and a deposit held), even newer than my Mercedes and packed with features however I am a MERCEDES AMG customer right? Eventually even a free VW is not cutting it right? I also called Mercedes benz SA, received the same feedback and that I will be contacted weekly however I have never received a single call from them or from the dealership on their own will. The only communication is when I personally make contact and then get them to call me back as you also never get through to anybody once. Imagine how this vehicle will be after already 3 months of not starting? Surely this is going to lead to further problems down the line. Honestly very disappointed, I also work for customers and we simply do not treat them like this, we cannot blame system issues (same message from January) for not being able to update customers on their own property.