Fix/repair 2 x wordpress contact forms running on Contact Form 7

We require a freelancer to fix up two recently installed contact forms on our Wordpress website. The forms are running on Contact Form 7. We need the forms to email out via either SMTP or PHP Mail. The problem with the forms is that they won't send the data when a website user enters the information, and they come up with the error: "Failed to send your message. Please try later or contact the administrator by another method." We have double checked with our hosting provider, and the ports are defiantly NOT blocked and everything should be working from their end. The project is URGENT and the freelancer must be able to commence straight away.