I am walking the stage at graduation but just figured out that I may have to take 18 hours this summer. Will they allow it?

I’m in CNS, and I am a little stressed because I am registered to walk and everything but I got dropped from an ACC class due to a missed tuition payment. If they don’t let me back in, I’ll probably have to take an extra class over the summer (have to take 15 hours worth of classes already). I can’t delay my graduation to fall because of my job. Would UT allow it?