The simple answer is NO, and do take this very seriously. All of the sites supported by Jarvee are popular websites with anti-spam systems that look out for proxies, and as such free proxies would not work as most are low quality.
Aside from the fact that free proxies are detected, they are also very slow because of the low-powered infrastructures they are built on, the number of people sharing them, and the fact that they are insecure.