I need help and support in working to interface directly with my interal contact system.
Also, does Constant Contact have the ability to pick up via data drop off file?
Constant Contact's API provides a great tool for interfacing with our systems to send or retrieve data. If you are wanting to use it to connect your internal contact systems to Constant Contact, the best option would likely be to use one of our pre-built wrapper libraries to reduce the time needed and get up and running.
You can find information on how to get started with the API here: http://developer.constantcontact.com/get-started.html
And you can find a list of our wrapper libraries here: http://developer.constantcontact.com/libraries/libraries.html
Lastly, Constant Contact does not support a data drop off file, but we do support the ability to submit a spreadsheet of contacts as a multipart/form-data POST request. You can read more about that here: http://developer.constantcontact.com/docs/bulk_activities_api/bulk-activities-addcontact-multipart.h...
API Support Specialist