LendKey Technologies, Inc. Student Loan Complaint

LendKey Technologies, Inc. Student loan department,

Non-federal student loan Dealing with my lender or servicer Trouble with how payments are handled New York

I paid my loan on -/-/-, and received confirmation. My loan servicing has now been transferred from - - - - to - to Lendkey, and Lendkey is saying I have not made a payment yet and that it is overdue ( although this information should have been carried from - ). I would like to know why my payment is not reflected in this new account. I would also like to receive verification of this debt now that it is with a new servicer, including the signed promissory note.