public decimal GetCustomerCurrentAmountDue(Guid customerId)
{
var customer = _customerDataService.GetCustomerAccount(customerId);
var mowingCharge = customer.GetMowingCharge() * 2;
var weedingCharge = customer.GetWeedingCharge();
var wateringCharge = customer.GetWateringCharge();
return(mowingCharge + weedingCharge + wateringCharge);
}