You want to mass assign dunning strategies to customers. But you don't find any option to enable this.
SAP Business Bydesign
Currently in SAP Business ByDesign, it is not possible to mass assign dunning strategies to customers. The assignment of dunning strategies is based on individual customer accounts.
See also blog post: Dunning in SAP Business ByDesign
account, accounts, customers, migrate, mass, upload, migration , KBA , SRD-MD-BP , Business Partner , Problem