Hello @Thomas1098,
If it's that you took advantage of the pay less upfront option then you'll have to contact Airbnb support to see if they can help.
Airbnb controls the payment schedule and doesn't provide anywhere on the site for guests to complete payment early themselves.
Type "contact airbnb" in the "Search the community" box on these forum pages where you posted your question. Scroll down a little in the list of suggestions that appears and click on the "Contact Airbnb: A Community Help Guide[UPDATED]" one. That lists phone numbers and ways to contact them via Twitter or Facebook.
Steve.