I searched for a thread on this but I didn't see one, so thought I'd let everyone know that you can (if you want) pay off the balance (if you're on a payment plan) of your Coachella tickets online at the http://coachella-weekend1.frontgatetickets.com (for weekend 1 tickets anyway) now. Once you sign in, if you click on Order History in the teal writing on the left of the screen, and then it should say "This order has a payment plan. Click HERE to manage this plan." If you click HERE, and scroll down, there should be an option to "pay the balance in full." I called Frontgate tickets to confirm this and he said my balance has now been paid in full!
Obviously I was on a payment plan because I couldn't pay everything back in May, but once I was able to work full time this summer I have enough saved to pay everything off (and now I don't have to worry about something going wrong with my payment or whatever)! I don't know if this will be helpful for anyone else but I hope so!