Toyota Estima CVT Gearbox

My estima (ACR50) 2.4 vvti auto transmission suddenly stalled while engine was running. I tried to change the transmission but it seems that the gear failed to engage. It feels like the transmission was at Neutral position.

When tested, all the sensors and circuits are normal, mechanic can't fault anything. The real problem was the CVT chain lifespan, the chain broke.

Solutions:

1. Change a whole new gearbox which cost will be more than RM20k

2. Buy a second hand gearbox around RM10k

3. Rebuild the gearbox by changing the parts for RM5k++