Diplomas

We have been trying to get hold of all the subjects marks on 3 different Diplomas, for the past couple of months. As the dates are 1999, 2001 and 2003, according to GigaS****s, they do not have the results, as it is too far in the past and they only keep the results for 10 years. We contacted Gigas**** and was referred to contact Vaal University of Technology, as they are suppose to have the results in archive. GigaS****s used the student's ID as Student No and according to VAT they need a student no and cannot do anything to help unless they have the Student No and even in that case they do not know if it would be possible to obtain the marks. How is it possible that records are not kept from students that have received Diplomas in the past from GigaS****s?