ECM communication problem

[Jacqui]

Good morning, I have a 2016 Terrain for 2 months now. Carmax replaced the battery and since then I’ve been having this problem where it’ll lose power and get stuck in gear. Once I come to a complete stop and turn the turn completely off, I’m unable to start it back up for an hour. Took it to the deal for them to tell me it’s nothing wrong with the truck but I continue to have the same problem. I just recently went to auto zone and was told that the ECM lost communication. How do I get this fixed and what’s all that needs to be done.