UC application payment--it won't let me pay

When i went to submit the app, the payment portal resulted in an error so i was forced out of it. Later, when i tried again to pay, the option to do so was no longer there. My app is submitted, but i can;'t pay for it. has this happened to anyone else?? what do i do?

Same thing happened to me, but the third time I tried it said my payment is pending. I am just going to check it 2-3 days later and try to pay again.