Contact From for High Traffic

So I'm using Contact Form 7 on one of my sites ozfm.com. It's a radio station, and it gets A LOT of forms submissions. But we're having issues with it, someone mentioned it's because of the high volume of submissions - it that a thing? What should I be doing? I could go with something like WuFoo forms .... cause it's a separate thing you embed it in the site. Would that help?

What should I do?