i've never used their affiliate program. according to their site, they dont pay right away. there is a lag, esp for those outside america. here's a quote from their site:
New signups must stay a minimum of 45 days for affiliate bounty to be paid.
Affiliates are paid twice a month after the first pay period criteria is met.
All affiliates will be paid 45 days from the end of any given pay period. EXAMPLE: Affiliates would be paid on May 15th for signups generated during March 15th-March 31. EXAMPLE: Affiliates would be paid on May 30th for signups generated during April 1st-April 15th.
Affiliates must generate affiliate bounty of $100 or more before first check will be sent. After the first $100 there is no minimum to be met.
As with any affiliate program, you need to jump through the hoops.
Most affiliate programs that I know of don't have such hops. I agree however with amish_geek that you should do whatever they ask you to do. $5000 is a lot of money, who cares if you have to be on the phone spelling your words, the effort is worth it IMHO. Hopefully you don't live in a country that they don't pay out to as that would be a very serious problem.
So, phone them if that's what they asked you to do. Good luck!