Most student borrowers never interact with whoever holds their debt. They interact with a servicer, and the distinction explains a great deal of ordinary confusion.
Two different roles are involved
The holder of a loan owns the right to repayment and is bound by the terms of the promissory note the borrower signed at the outset.
A servicer is a contractor that handles billing, payment processing, correspondence and enrollment in repayment arrangements, and it operates under a contract with the holder.
The servicer therefore administers rules it did not write and cannot change, which is why a request for different terms produces a form rather than a negotiation.
Servicing changes hands and the loan does not
Servicing contracts are reassigned, and borrowers receive notice that their account has moved to a different company with a different portal and different phone number.
The underlying loan, its balance and its terms are unaffected by that transfer. Payment history should transfer with it, and records that do not survive the move are the borrower's problem to reconstruct.
Keeping personal copies of payment records and correspondence is therefore practical rather than paranoid, since the counterparty may change several times across a repayment period.
Federal and private loans differ fundamentally
Federal loans carry statutory protections and repayment arrangements defined by law, which apply regardless of which servicer holds the contract.
Private loans are governed by their own contracts, and whatever flexibility exists is whatever the lender chose to include, which is generally less.
Borrowers frequently hold both and assume uniform treatment, which is where missed options and unexpected inflexibility usually originate.
Enrollment in options is not automatic
Repayment arrangements based on income, deferments and forbearance generally require an application, documentation and periodic recertification.
A borrower who stops paying without applying for anything is treated as delinquent, not as enrolled, and the consequences differ substantially between those two states.
Where to get authoritative answers
Federal program rules are published by the Department of Education and change over time through regulation and legislation, so current official guidance outranks any general description.
For a disputed balance, a servicing error or a decision about consolidation or refinancing, a nonprofit credit counselor or an attorney experienced in student debt is the appropriate professional.
Free help exists and companies charging fees to enroll borrowers in free federal programs are a recurring problem, which is itself a reason to start with the official source.