Netstarcustomer service never responds

I am desperately trying to get Netstar to change my bank details and car ownership as my husband is critically ill. They have ignored three emails and I have made numerous phone calls and the phone just rings for up to 15 minutes after which I gave up. I got through once and just got passed to another department where the phone rang for another 10. If this is what their customer service is like I hate to think what service I'll get if my car gets taken