General Motors review: unethical behavior

my 2008 Chevy Tahoe Hybrid was towed to Laura Chevy dealership in Sullivan, MO the week of Thanksgiving 2018. I was enroute from Chicago, Il to Arkansas for the holidays. Service center rep Marko informed me they need to order a special part to diagnose the Hybrid. Upon hearing this I returned home to Chicago, 5 hours away from the service center. I was informed 3 weeks later that the Power Control Module needed to be replaced along with the body control module. I was asked to provide funds for the parts up front, $5200. Repairs were made and parts installed. Car would not start. The week of Christmas I was then informed that the Transmission Generator needed to be replaced due to no start, no crack issue. part was ordered. Part arrived, instillation was made. Car would not start. First week on Jan 2019 I was called and told the Transmission was now out and also needed to be replaced. Transmission was ordered, part arrived Jan 14th and I was told repairs would be completed by Jan18th. Now its Jan 22nd and I have no call from the service center giving me an update. More bad news is likely coming. This is a very big disappointment. I feel as though I am being lied to and begin held ransom.. as this service center cannot properly fix my GM vehicle and they are throwing money and parts at it hoping to succeed. this is all at my expense. I am being taken advantage of by a incompetent service center. Please help me