Why would student finance compliance team get in touch with my old bank account ?

Hi, I have recently been told that my application is with student finance compliance team, which is fine as I don't have anything to worry about, but I am just curious why would they contact my old bank account provider that I no longer use, the account was closed with them too but by the bank itself (still unsure until these days, why). As far as I know I always been honest with student finance and provided legitimate documentations so l am sure that there is no reason to be worried, but I am just curious as the payments now is blocked and I am in financial hardship and worried that the financinal hardship application will be not successful until the payments are unblocked. Did anyone went through this and could share insights? It only happened because I recently changed courses. I transfered from one university to another and now going to study nursing instead :/ until this change they never picked my application and went for investagion.