Mando

I was driving in a highway, a distance of 560km from home. So, right in the middle the car decided to go on 'limp mode' and it doesn't shift from the first gear. Luckily, I called someone who told me to try to switch off the engine and start on 'N', the car then started on the 2nd or 3rd gear (no reverse). It would need some effort to move but then it would easily reach 90-100 km/hr so I was able to finish the road. However, I took it to two dealers afterwards and they had opposing views regarding what happened in the transmission system:

1) RS CTRR. Unit Electrohyd. which is basically like an electronic plate in the transmission system (like a motherboard) that needs to be replaced

Cost: $915 excluding labour or installation

2) The whole valve / mechatronic.

Cost: $2,050 excluding labour and installation

Please help me if you experienced the same and which option makes more sense?