“Uwo Private Parking Tickets”

Hi,

I've recently received a letter from the University of Western Ontario (UWO) in London, Ontario advising me that I have 3 over due parking tickets ($20 each) and a MTO fee ($20) to pay before the 27th of November. If not paid they will contact a collections agency and lock up my student records (the car isn't under my name so I don't think thats an issue). The problem is I have only ever received one physical ticket on my car, the office tells me "they don't have to prove anything to me, either you pay or you will get a credit hit". Is there anything I can do?

Thanks in advanced!