hard downshifts, check engine light, loss of power

We purchased our 2008 Mercury Mountaineer in March of 2011 with about 36,000 miles on it. Around 65,000 miles the car started to leak transmission fluid in the garage so we took it to a local transmission shop and they said the transmission needed to be replaced and they charged us $3,000!!! The car was fine until about 80,000 miles when the car downshifted very hard when coming to a stop and would jolt us forward every single time. We took our Mountaineer back to the same shop. Our car was in the shop for over a month! We went back to check on it and it was just sitting there and they haven't even looked at it. They replaced the solenoid pack and returned the vehicle. Upon departure the car immediately downshifted hard and we turned around and took it right back. They then replaced a rod in the transmission I believe cant even remember because the whole thing was such a headache. The car was okay for a little while. Then it just got worse the car would get stuck in fifth gear and a orange wrench (Which means powertrain malfunction) showed up in the center display along with the check engine light. The car would then downshift and rev up to about 5000 rpm and then upshift again. The car could barely make it up hills and was absolutely terrifying to drive. I have never owned such a unreliable car in my entire life. We traded the car in June of 2014.