Repayment of a maintenance grant error

Harper59

My daughter was at university between 2010-2014 and we provided details of our household income. Since this time my daughter has worked in various cities in the UK and recently 2.5 years abroad in Australia. My daughter had dealings with Student Finance whilst abroad and in the UK regarding declaring her salary etc, to repay the student loan. However, there hasnt been anything mentioned about an overpayment of £1700 because they made an error on the maintenance grant. They only mentioned it last week whilst talking about her salary income. Apparently the first letter sent to her student address (not lived there since 2014) and we have received nothing else. Question is, can they go back 7 years and how do we know this amount is correct that we owe. Surely before it goes to a debt collection agency, they should have been in contact. Whilst abroad, all her student finance letters were sent to her family address. So why did this debt letter not arrive? Can anyone advise?