You will make payments to UAG for things such as tuition, paying for "extraordinarios" (your 3rd chance to take a final exam), and a $300 "seat holding fee" (even if you already paid for the next semester, they have a strange rule of making you pay an extra deposit to hold your seat in the class - it is usually deducted from your tuition but you still have to get the receipt and take it to the office).
All this is not too bad. However, UAG does not make complete use of networking computers. If you pay something at one geographical part of UAG, another section still does not know that you paid it unless you take them a physical copy of your receipt. This still would not be too bad if it was better communicated to the students. Therefore, for any payments made, it's your responsibility to keep track of your receipts and ensure whatever departments needs one has one (!). Note the difference from Canada/US where it's up to the organization to stay informed. Do not be aggrevated by this! It's just a different system which can get you upset if you don't realize it.
Take your receipt copy to this office at ICB which is near the west entrance - this is the Oxxo and papeleria entrance near the ATM (there is only one ATM at ICB).
Remember: take them a copy of EVERY RECEIPT!
The receipt you are taking them will look like this (names changed to protect the guilty):