My second portable oxygen concentrator broke and was retUrned to the company in December 2015. Every month after that they continued billing my insurance company and sending me the statement. I called continuously from that month to March 2020 asking them to fix my account and stop billing me for equipment I didn’t have. Everytime I got a hold of someone they all said they would look into it and get back with me, and No ONE ever did. I finally contacted my insurance company to report the fraud. They are difficult to get a hold of and even more difficult to fix a problem. Stay far away or you will be going down a rabbit hole.