BAD REQUEST Error Equals BAD CUSTOMER SERVICE!!!

It's been months since I tried registering on SunBet but always get a Bad Request error. I emailed and chatted to their support Team and the response I get it's been escalated the IT department is aware try again cos nothing they can do. They disconnect the chat after that. Issue is as a Silver MVG member I get vouchers to redeem but how can I redeem them if the website doesn't allow you to register??Bad service!!