AutoNation Hyundai 104

I have a Hyundai Accent 2002 and have a transmission warranty 100,000 miles or ten years. I originally brought my car in because the RPM's were spiking from 3000 to 3500. They diagnosed it and said it w warranty 100,000 miles or ten years. I originally brought my car in because the RPM's were spiking from 3000 to 3500. They diagnosed it and said it was slipping in and out or 3rd gear. The replaced my transmission with a remanufactured transmission. I picked up my car and drove it to work. The same spiking RPM's occured. I sent my car back in and they said it was the spark plugs. So $85 dollars later they replaced my spark plugs and again I headed to work. Well the same thing happened, my RPM's continue to spike. I called them and they said to bring it in the next chance I have. So I brought it in the next day and they had it for 3 days. They called and said they could not get it to duplicate when they test drove it. So I came back to pick up my car. Barely made it out of the parking lot, lost all power and my check engine light came on. So I turned around and took it back to the shop. They said they would find the problem and let me know what happened. So one of the sensors broke, they replaced that and I picked up my car again. Once again the same problem my whole drive to Fort Morgan. I called and said I will be there Tuesday to take James for a drive to show him what happens. So i pick him up on Tuesday and drive him almost all the way to Fort Morgan. It happened 4 times on the ride. He said he would talk to the technicians and see what they think is causing it. He calls me back 3 days later and says the torque converter is messing up but its normal for the age of my car and miles. The car is a 2002 and all of this started at 85,000 miles. Im sorry but that is not normal and if it is then I am going to tell all my friends never to but a Hyundai because they wont run right after 85,000 miles. So the weekend following this call, I drove my car to Nebraska and back and the ENTIRE drive to Nebraska the RPM's spiked from 3000 to 3500. I called James and he said to bring it in when I get back in town. I dropped it off Tuesday April 19th. I didnt receive all call regarding my car for almost a week I finally called on Monday April 25th to check on the progress. James stated they had drove it around town and that he was going to drive it to Fort Morgan at 2:30pm. After the drive he called my dad and said "Well we cant get it to duplicate, so we cant make any repairs" So tomorrow I am taking the loaner car back and picking up my car. How can they say they cant duplicate it when it happened 4 TIMES on my drive that I took James on. Im sorry but very very poor service. More