Assistance to create and manage effective cold calling email for loan company

I am looking for someone who can assist us to get results in our email marketing campaign for a loan company. We use Mailwizz, Mailzoom, swipemail and have setup a dedicated server for mailwizz. We are targeting South africa only and require someone to assist us to get results in our efforts. We have 13 domains we use to send these emails and they are cold mass emailing. This is all running but we are not getting results. We want someone who will be able to get conversions for us. I will require a test that shows results before we commit to a long-term project. This project is ongoing however due to failed attempts from other hires, we need to ensure the person we hire produces a result. Knowledge of these platforms is required. The person will be required to help create converting templates