I think I recognise your username from the old yagc forums! probably going back 7 years or so now!
Anyways, what are you using? The .net IE browser? Or something else?
I would recommend selenium with firefox driver.
Using a headless browser I had issues (phantomJS)
With firefox driver, all working fine.
But the new captcha is tricky to automate. Have to pull a few iframes, action in those, step out, move the mouse and it will work.
If you need more help, with /without selenium, just post in here or the c# and can let you know in more detail how I did it (if needed)