"Expert Digital Marketing for Medical Billing"

I run a medical billing service (financial services) targeting US physicians. I am looking for someone to set up and maintain a digital marketing program. We have tried a few campaigns and ended up paying for many clicks that do not convert. For that reason, we are looking for a company to create a digital marketing campaign whose fee will be largely based on the number of converting leads. We would use SEO, email marketing, and various other techniques. Let me know if this is of interest to you and how much you would charge us for this.