Seidners Collision

In May I took my vehicle to get fixed because I was in a auto collisionAfter collision repairs were performed I noticed that the transmission was making a noise and the check engine light turned onI took it back and seidners collision took it to Covina Nissan to get inspectedThey returned the vehicle and said there was nothing wrongA week later same problem occurred so I took it back to seidners collisionSeidners said there was nothing wrongThis happened two more timesThe last time I took it Seidners finally decided to replace the transmission with a NEW TRANSMISSIONSeidners said the new transmission had a three year warrantyNow the transmission is slipping and the check engine light is on with the same dtcI took it back to seidners collision and they said that the transmission only has thousand or month warrantyThey also said that the transmission was not new it was refurbished