用对方信用情况提醒对方

Dear Mr.Wang,

　　Since you have ignored several requests for payment,we must take other ?action? to collect your past-due account of $15 000.Unless we hear from you in 10 business days,we will turn your account to a collection agency.Neither of us wants to see your credit in danger.So if payment has not yet been made,we urge you to send your check as soon as possible.?　　

　　Yours sincerely,