IS it a correct REA model?

Upon electronic notification of shipping, a billing clerk charges the customer account for 50% of total charges.The remaining 50% will be billed in 30 days.The billing policy is standard and applies to all customers.A cashier records customer collections received into FFI's(company's name) main checking account.In order to improve internal controls, FFI maintains a separate payroll cash account.An AR clerk manages past due accounts.

Required:

Conceptual model: Draw an REA model with cardinalities for the operating events, agents and resources in the sales/collection process described above. Use crows feet notation for cardinalities.