general problems of the 2010 Mazda MAZDA6

My vehicle is automatic transmission and last weekend I was driving at the freeway with my family at 70 mph on cruise and all of a sudden we got big jerk from my vehicle and the vehicle rpm started increasing the same time first I thought someone hit me from back but the gladly the vehicle was in other lane and he honked at me. I then I saw d light disappear on the panel and the vehicle was in very high rpm mode. I didn't know what is happening I safely tried to pull on the right and stopped to see whats wrong but couldn't found anything. I turned off vehicle for a minute and started again. It worked fine for 5 min and as soon as I reached 55 or 60 mph the d light started blinking again and again I got high rpms and jerk. It almost had caused the accident as the other vehicle almost hit me from the back. It felt like engine braking. Then I drove very low spped on inner city road with my blinkers on to reach home safely. Now dealer is telling me that it will cost me minimum $3000 to replace the transmission. I think its a know issue to Mazda and they should fix my vehicle transmission atleast. This vehicle is not safe to drive.

8/11/2018while merging from route 9 onto route 95, I heard a clank coming from the bottom of my car, didn't think since driving through deep flooding from current rainstorm. Was on I-95 when steering seemed to go, veer to the right and brakes not catching. Was able to get off highway, regained control of car, went to my destination on rte 109. Drove, pumped breaks since I thought the problem was flooding & wet brakes. Left to go to next destination & steering was off, so drove very slowly (steering off & had to keep turning to the left) once again thinking weather related. Exited 95 to sprauge st. Dedham where brakes weren't working well, drove to friends in area and as I drove down hill, car lost steering and I landed up curb, brakes weren't working, put on emergency brake & finally stopped. Friends house was around the corner so rolled down hill to her house to let car dry as still thought it was from flooding. Left her house after an hour, drove two blocks and car completely lost all steering, lights on dashboard started flashing, brakes went. Called aaa and was towed to steve's service station where on Monday the car was deemed "totaled". The entire sub-carriage was covered in rust & corrosion, there were holes, pieces of metal from the car missing and major cracks all underneath and encasing the brakes and other part of car. Was told if I had gone a bit faster on 95, bottom would have fallen leading to serious accident. Note: there are numerous complaints about this with Mazda6 and Mazda has done nothing. I cannot receive financial compensation from insurance since is corrosion and not collision that caused the problems. Financial disaster. 47k miles, one owner car. Consults from mechanics said they have never seen anything like this on 8 yr old car. Appraiser said Mazda known for rust problems - gave me websites to research to assist. Please help!.