I am having this same issue and I am afraid that I may have to find an alternative theme even though I have used this for over 10+ clients websites, I just got a call from a client saying that a client of theirs called them and said they got no response after submitting a contact form.

I then tested the contact form to find that emails are not consistently being received.

I have since done multiple tests:
the wordpress version was 3.9.1 and the theme version for 2.8 and there were missing emails
the wordpress version was 3.9.1 and the theme version for 3.0.8 and there were missing emails
ive updated wordpress to 4.1.1 and the theme version for 3.0.8 and there were missing emails

If my clients can’t reliably receive emails from the contact form then this theme is functionally broken, the contact form is the most important aspect of the website. I anxiously await a solution otherwise I will have to redesign the sites with a new theme all together, and stop referring people to this theme (I like the theme, but this is a serious issue and it looks like it hasn’t been dealt with/fixed for months – search for “contact form broken” or “not working” in the comments section of themeforest).