Corrlinks Email Automation Program

I'm looking for a program that can connect to Corrlinks, the federal prison emailing system. This program should be capable of connecting to 20 different accounts at the same time and sending emails to subscribers based on their individual plans.

Key Requirements:
- Ability to connect to 20 Corrlinks accounts, and to several groups in each account simultaneously.
- Automated sending of emails to subscribers, tailored to their specific information/message plan.
- Ideally, the freelancer would have experience with email automation software and programming.

This project necessitates a high level of organization and attention to detail, as the emails will need to be sent according to the various plans of different subscribers. The subscribers are organized in groups. Each group can only contain 10 or less members so many of the same emails must be sent at the same time to many different groups (close to 1000 subscribers)

I ALREADY HAVE A PROGRAM THAT WAS BUILT ABOUT 4 YEARS AGO. A NEW PROGRAMMER COULD START WITH THIS TEMPLATE IF WANTED/NEEDED! Corrlinks changed and added new limitations . My program needs to be updated and become more performant. It does not work well with the latest Windows either (it crashes a lot since the Windows update). I have been told it was written in Java and SQL.

This contract could lead to a more permanent work agreement for maintenance, upgrades and so on... I am a single-soldier army (lol) and looking for someone easy to collaborate with. It can either be paid by the hour or fixed price. (i had to choose one below but everything can be discussed)