CVT Nissan Sentra Box 2007

Good day

friends

I have a big problem, a few days ago I changed the CVT box of my Nissan Sentra 2007, the one I had left without oil and it is damaged, buy a new box, the problem now is that there is no power in the car, like the computer and the box did not synchronize, because when you accelerate it costs a lot to do it and brake of a single Fact is that I have my car standing for 3 weeks for this and spent a lot on buying that box.! What can I do.