I have called.I have text,I have been ignored when calling about warranty replacement of 5G column ! I have called inogen in california and they said one year warranty was your responsibility.You also gave me a 3 Year warranty when I bought the G5 S/n23094093 ,model#10-500. George Esper 11926 Pondwood dr,Cypress,Tx 77429 Phone 1 5045598335