I had also emailed him twice and didn't get a reply. Then I realised that I had not included my Date of birth detail. So I emailed him again today with the DOB and I got the reply within a few hours.
Hope you have included the below details in your mail:
Name, email id, country of birth, date of birth, application number, Unique client identifier, Mobile/contact number and type of application.
Also, they work from Monday to Thursday only. And try to email them during their morning hours. Preferably by 8 am their time. You should then get a response soon.