12.  Nationstar funded over $19 billion in mortgage loans in the year that  ended on December 31, 2017, making it the twentieth-largest mortgage loan originator  in the United States.  Occasionally Nationstar sells its underlying mortgage loans on  the secondary market, but in such cases generally retains the post-sale servicing rights  on the sold loans.   18.  In August 2014, Plaintiff received a loan from Velocity secured by real  residential property in Los Angeles, California, pursuant to a “Note” and “Loan  Agreement” that Plaintiff had entered into with Velocity (collectively, the “Loan  Documents”).  The loan Plaintiff received from Velocity in August 2014 is referred to  herein as the “Loan.”5   60.  Plaintiff brings this action on behalf of four classes of persons pursuant to  Federal Rule of Civil Procedure 23.   61.  To redress and put a stop to Nationstar’s practices of billing borrowers for  a single monthly interest charge multiple times, Plaintiff brings this action on behalf of  herself and the following class (hereinafter, the “Double-Billed Class”) pursuant to  Federal Rule of Civil Procedure 23:  All individuals in the United States who, at any time between  February 7, 2015 and the present, (i) entered into a mortgage  loan; (ii) in connection with that mortgage loan made  monthly payments to Nationstar in the amount demanded by  Nationstar; (iii) in connection with that mortgage loan paid  to Nationstar a monthly interest charge; (iv) after timely  paying in full that monthly interest charge received from  Nationstar a successive demand for payment of the same,  previously-paid monthly interest charge (i.e., pertaining to  the same month of the same year of the same loan); and (v)  paid the full amount demanded by Nationstar for that  previously-paid  monthly  interest  charge,  without  reimbursement.   77.  Plaintiff repeats and realleges the allegations set forth above as though  fully set forth herein.   78.  Plaintiff contracted for mortgage lending services on the terms set forth  in the Loan Documents (i.e., the “Note” and “Loan Agreement” governing the Loan)  that Plaintiff and Velocity entered into on August 11, 2014, the rights and obligations  of which were subsequently assigned to Nationstar on October 21, 2016, via Seneca  and/or other intermediary entities.   79.  Like Plaintiff, each member of the Double-Billed Class contracted for  mortgage lending services with Nationstar directly or with another entity that  subsequently assigned the pertinent mortgage loan to Nationstar (or to another  predecessor entity which in turn assigned the pertinent mortgage loan to Nationstar),  on the same or substantially the same terms as set forth in the Loan Documents that  Plaintiff and Velocity entered into on August 11, 2014.    80.  In plain, clear, and simple language, in the Loan Documents and other  governing loan-related documentation in effect between February 7, 2015 and the  present between Nationstar and Plaintiff (and others similarly situated), Nationstar  promised Plaintiff and all other Double-Billed Class members that it would refund any  overpayments made by the borrower in the course of paying off his or her loan in full.   87.  Plaintiff repeats and realleges the allegations of paragraphs 1-76 set forth  above as though fully set forth herein.   88.  Plaintiff contracted for mortgage lending services on the terms set forth  in the Loan Documents (i.e., the “Note” and “Loan Agreement” governing the Loan)  that Plaintiff and Velocity entered into on August 11, 2014, the rights and obligations  of which were subsequently assigned to Nationstar on October 21, 2016, via Seneca  and/or other intermediary entities.   89.  Like Plaintiff, each member of the Post-Payoff Interest Class contracted  for mortgage lending services with Nationstar directly or with another entity that  subsequently assigned the pertinent mortgage loan to Nationstar (or to another  predecessor entity which in turn assigned the pertinent mortgage loan to Nationstar),  on the same or substantially the same terms as set forth in the Loan Documents that  Plaintiff and Velocity entered into on August 11, 2014.    Breach of Contract   (On behalf of Plaintiff and the Double-Billed Class)   Breach of Contract  (On behalf of Plaintiff and the Post-Payoff Interest Payment Class)   Breach of Contract   (On behalf of Plaintiff and the Late-Fee Class)  