Help! I paid my tuition on time but I discovered today my class registration got cancelled!

I woke up this morning to go to the Rec center to work out, and my ID card wasn’t swiping. Then I told the front desk my UT EID, and it said I’m not a full time student so I wasn’t allowed to use the facilities. I thought that was ridiculous, since I actually am a full time student. Even though I paid my tuition through credit card two days ago(Graduate school tuition deadline was yesterday) and have the email receipt confirming I paid, apparently I must have forgotten to click the “Confirm Attendance” button, which I didn’t realize I had to do(which is also confusing because I didn’t have zero amount due for my tuition). It’s Saturday so it seems I can’t do anything until Monday when the administrative offices open again, but what plan of action can I take now?