BuddyPress.org

I’m going to install Buddypress for an client and he asked if I could import their memberslist (over 800 members so far) it’s in excel.
Today my client have 2 sets of the memberlist, one in excel that they use and the company that sends out the reminder letters to those who haven’t paid the membership fee.
They wan’t to import the excel file into Buddypress so he don’t need to register one and one.

The second issue is that he want if an member doesn’t pay the membership once a year (reminder sent out from an company which is not part of a buddypress, it’s a separate system that we do not have access to) the member can’t login in.

Is this possible, is there plugins, codes etc if it’s so please guide me.

English isn’t my first language so I hope you understand what I’m asking after.