our mortgage was sold to a different company. we got a letter saying to pay the original company through a certain date and then submit all payments to new company. we paid the original company as requested and have bank statements to prove it. the new company started calling requesting payment and we told them we had paid the original company as directed. we encouraged the XXXX companies to talk to see that the payment had been made. we were told things had been resolved, yet its listed as a late payment on my credit score. 
