Hello!
So we have several stores (dynamic, manageable in the CRM), customers categories (what you called A and B, which I'd rather say it's better to consider they could become more categories in the future, and they should also be dynamic and manageable in the CRM). We then have the users (which I think should be assigned to a store they belong to) that enter the customers and fill in some data. The users will have limited access to only some of the operations in the CRM, most likely, and there'll be some admins granting them roles/privileges.
About the timer, should it be set with a date and time or only date? Should there also be a report ex "show me customers expiring 7 days from now on" ?
About the export function: I assume that your users would want to export customers lists, and they should only be able to export the list of their own store, not the list in all the company. Maybe some more privileged users (admin users) would also be able to see all customers from all stores?
Regards,
Dragos