Remote Pings to MailChimp

Trying to add membership subscribers to a list at MailChimp with remote pings. Followed the instructions to the T. I've tried GET which didn't make sense since we were sending information. There was no status in the ping history and nothing added to the list I was sending to. So then I tried POST which gave me a 200 - OK status but no change on the list as well.
Here is my ping info.

Ping name:
Foundation Subs

Ping URL:
http://us6.api.mailchimp.com/1.3/?

Ping data:
method=listSubscribe
apikey=MYKEY-us6
id=LISTID
email_address=%useremail%
double_optin=false
update_existing=true
send_welcome=false

apikey and id I have changed here but they are correct in my ping data.

Thanks in advance for any help