【正确答案】[范文]
   
   I'm sorry to inform you your account is overdue, with a current amount of $280. We request your immediate payment within no more than one week, since we have given you enough time before this ultimatum.
   You are welcomed to choose either check-mail or transfer to pay back the amount. If by mailing, please send it in enclosed envelop along with your personal signature.
   As I mentioned before, your payment must be received within one week. Please pay attention to the deadline to avoid extra fees and possible legal actions against you. Thanks for your cooperation.