Copywriting for Lead generation emails

Hi, We are a BPO and technology solutions company and we send emails to targeted companies to generate more business for the company. The response rates are poor and we would like to work with somebody that can write email content which is more personalised and interesting and hence generates more interest in our services and products.
We would like to work with somebody that has been doing copywriting and experienced with it. We will pay a upfront fee and also a fee for every response that is generated.