When you buy a home with a mortgage, there is a pretty high likelihood that the mortgage company will sell your mortgage to another servicer. Most loan originators will qualify you and loan you the money, then after the sale is complete they will sell your note to a servicer. A servicer is a large entity like Fannie Mae or Freddie Mac. It could also be another lending institution such as Wells Fargo.
When your loan originator (the company you got the mortgage from) sells your loan, THEY will inform you who the new loan servicer is.
The scam begins when the new home owner gets something in the mail from an institution other than the loan originator saying they are now servicing the mortgage and to send all your payments to them. If an unknowing homeowner were to follow these instructions they would make monthly payments yet they would be defaulting on their loan.
The ONLY time you should ever change who you’re paying for the mortgage, is when you’re notified by the servicer or loan originator you have been paying to. Again, your originator will inform you of who the new servicer is going to be and where to direct payments.
If you’re not sure about this, contact your Real Estate agent or your Mortgage rep to confirm.