Student loan additional drawdown on statement... 5 years after finishing uni??

I left uni in 2012 and have just received a statement that has £3k 'drawdown' this year which means that despite making payments each month my overall balance has actually gone up this year.

I called the SLC who said that sometimes universities are a 'bit late' with charging their fees correctly. I asked for them to send me all the information about what I've been charged and when, and they have told me I'll be charged by them to provide me with that information.

Has anyone else had this happen? Is it really possible for a university to charge you more 5 years down the line?

Thanks