// Apex Class to calculate Total Outstanding Amount
public class BillingAutomation {
    public static void calculateTotalOutstanding(List<Billing_Information__c> billingList){
        for(Billing_Information__c bill : billingList){
            // Implement the calculation logic based on provided formulas
            bill.Total_Outstanding_Amount__c = bill.Monthly_Card_Fees__c + 
                                                (bill.Charges_per_Transaction__c * bill.Total_Transactions__c) + 
                                                bill.Amount_Swiped__c + 
                                                bill.Cash_Withdrawal__c;
        }
        update billingList;
    }
}
 
// Apex Class to handle many-to-many relationship
public class CustomerCardAssociation {
    public static void associateCustomersWithCard(List<Customer_Card_Association__c> associations){
        insert associations;
    }
}

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