pan card authentication using tdscpc.gov.in

I want verify PAN Card using https://www.tdscpc.gov.in/app/login.xhtml i have its login credentials but captcha isn't visible before entering username.

i want to login using c# Code automatically. if captcha asks only thats ok. then i will make request of PAN Card and it should return status of PAN Card if it is expired, valid or not valid.

Please give some advice how can i achieve this.

Thanks Amit