The most likely section of regulations is 34 CFR Part 682, which is about educational loans. This only regulates what are known as "Federal Family Education Loan" programs, where the Dept. of Education guarantees against losses on loans made under 4 specific programs (Stafford Loan, SLS, PLUS, Consolidation Loan Program). Let's assume that somehow your loan falls under one of these programs so that is is federally regulated. Then, you would owe the money lent to you and you can be charged interest, under §682.202. But there is a provision for returning borrowed money, in §682.202(c)(7) that
A lender must refund by a credit against the borrower's loan balance
the portion of the origination fee previously deducted from the loan
that is attributable to any portion of the loan—
(i) That is returned by a school to a lender in order to comply with
the Act or with applicable regulations;
(ii) That is repaid or returned within 120 days of disbursement,
unless—
(A) The borrower has no FFEL Program loans in repayment status and has
requested, in writing, that the repaid or returned funds be used for a
different purpose; or
(B) The borrower has a FFEL Program loan in repayment status, in which
case the payment is applied in accordance with § 682.209(b) unless the
borrower has requested, in writing, that the repaid or returned funds
be applied as a cancellation of all or part of the loan;
(iii) For which a loan check has not been negotiated within 120 days
of disbursement; or
(iv) For which loan proceeds disbursed by electronic funds transfer or
master check have not been released from the restricted account
maintained by the school within 120 days of disbursement.
Hence there are circumstances under which one could end up owing interest for money that ends up being returned.
The wording of the response "refunds take 3 - 6 months to be received as this is a US regulation" sounds like a confabulation, there being no US regulation requiring a 3-6 month delay to transfer money from the US to the UK.
