Transmissions service instructions please?

We just bought a brand new van SXT Premium Plus. It only has seventy seven kms on it. We had it for one night everything was great until we reversed into our driveway. When we reverse the van struggles and shutters while trying to reverse pressing the gas as well as having to really press down on the gas to make it move but it shoots back really fast like we are on a hill. They told me a service would fix it so I need to do the job.

Thank you.