If she paid it on your behalf , then you should get a receipt whether electronically or to your student records or account. Even if she went to the bank and paid it on your behalf then a copy of the receipt from the bank should work. She can take a picture for you. Or scan it and send to you via email. If you were admitted , then you would have gotten a student ID number, usually you pay with that information, along with your name, so it should be on record.