I bought a inogen one g5 oxygen concentrator in December 2022 (They said it's new) it's start giving me trouble i call them they said need service.Send it back we'll check it and after 2 months they sends it back as itis after one month it's giving me same trouble. Three times I sends this machine but no use now they said call Inogen company but at time of sale they said its three years of warranty and they don't want to talk with me