Wasted money on a turbo they cant fix

I drive a polo tdi. Turbo broke because of age and km. Went to Turbo Extreme so that they could Recon the turbo. They charged me R4200. They said they can do a upgrade modification for R300 extra. So I approved for the upgrade. Got the turbo back. Drove 500km then it broke again. Took it out they fixed it again. Drove 500km broke again. They said they'll fix it for one last time by replacing the core with a new one. Drove again 500km when I started hearing a funny noise. Sent it back they were unprofessional. Blaming the car everytime something different. I have a 1year guarantee but they said they are finished with me they want R4200 before they see the turbo again. Cost me 5 times to take the turbo in and put it back as I live in Delmas its quite a drive. Talked to some guys said they had the same experience. Every time it broke they had a different story. The one year guarantee means nothing to them. They cant fix a turbo and blames it on the car even after I paid for a diagnostic test on the car to prove them wrong.