CVT Nissan Sentra Box 2007

Good day,

friends.

I have a big problem. A few days ago, I replaced the CVT transmission in my 2007 Nissan Sentra. The old one ran out of oil and was damaged. I bought a new transmission, but the problem now is that the car has no power. It's like the computer and the transmission aren't synchronized. When I accelerate, it's very difficult to get it to move, and if I brake suddenly and then accelerate again, the transmission doesn't respond. I don't know if it's an electrical problem or a problem with the computer. The fact is, my car has been out of commission for three weeks because of this, and I spent a lot of money on the transmission! What can I do?