Not interested when problems occur

Have used several times without a problem. However this year when I booked my car for pickup at LAX before checkout Argus offered a GPS for a few pounds a day. I took this option and paid in full. My car hire voucher with Budget stated GPS included. Just before my holiday date I checked my reservation online and the GPS was stated as being booked but not paid for. I emailed Argus customer service who confirmed a few days later that the GPS was included in my package. When I got to the Budget counter they were adamant that I had to pay for the GPS (US$120 for the 15 days about the same price as a GPS in Walmart) or no car. So I paid up and emailed Argus customer service. They sent me a link to their complaints system which I completed when I returned to the UK two weeks later. No response to my complaint, they simply closed it. When I noticed this I reopened the case but next day it was closed again without any contact. So I am an ex customer of Argus car hire.