Dear XX (客户名),Sorry to push you, but the outstanding payment has been delayed for xx(时间),please help to check and arrange the payment as soon as possible.If you have any questions about this, please just let me know, your quick reply is very appreciated.You may refer to attached document for payment details.(有的客户很忙,会对应多个开发商,最好把发票之类的资料附在附档中)