Hello

Hope you’re doing well.

There is no particular contact number for bank officers. If you have any fee related query or problems you can contact  the nodal officer of a particular college and they will guide you further.
you can find their contact details in below mentioned link.
plz write in the comments section if you have any more questions

http://www.du.ac.in/du/uploads/COVID-19/pdf/UG_Nodal_Officer2020.pdf

This ^ link is for UG admission process and fees.

Thanks