What's the issue we are looking to resolve? Non-responsiveness? Wrong contact?
I think it's important to send one and done enrollment - from my history with affiliates you get their attention for a very short amount of time then they ignore all other inquiries until the final hour. The initial sign-up should obtain money, give dues days by which things are needed, have an area for them to submit their session info (if any). An more importantly clearly spell out what happens if we don't receive their information by xx/xx/xx.
My fear is that two contacts will lead to "":well I though y was doing that, or I didn't reply because I thought x was handling it""
It gets even worse when you add in phone because 75% aren't at the phone so you leave a message. Managing the affiliate registration is a full time job during this time of the year.