What to do if…
your mortgage payment amount changes suddenly and the next payment is due within days

What to do now

1. Capture what changed (2–5 minutes).
   In your lender’s app/online account, save or screenshot:

   • the page/statement showing the new monthly payment
   • any message/letter about a rate, product end date, or payment recalculation
     Write down: old amount, new amount, and the date it takes effect.

2. Sanity-check likely triggers (quick scan).
   Look for anything that would plausibly change the payment:

   • a fixed/tracker period ending and the mortgage reverting to another rate
   • an interest-rate change notice for a variable/tracker product
   • a change to term, overpayment arrangement, or a fees/arrears adjustment
     You’re not trying to solve it here — just gather clues for the call.

3. Check how the next payment will be taken.

   • If it’s Direct Debit, check your banking app for an upcoming collection (amount + date).
   • If you pay by standing order/manual transfer, check whether you need to change the amount to avoid underpaying.

4. Check whether you were given Direct Debit “advance notice” of the change.
   Search your email/post/online inbox for a Direct Debit notice. Under the Direct Debit scheme, changes to amount/date/frequency are normally notified in advance (often 10 working days) unless a shorter period was agreed. If you can’t find notice, note that for the lender/bank.

5. Call the lender today and get a written breakdown.
   Say: “My monthly payment changed suddenly and the next payment is due in days. Please confirm the exact amount you will collect on [date] and explain exactly what changed (rate/product ending, term, fees/arrears, or correction). Please send the breakdown in writing to my online account or by email/letter.”
   Also ask: “What notice was sent to me, and when?”

6. Decide how you’ll handle the due payment before you end the call.
   Ask the lender:

   • “To avoid arrears, what amount do you expect me to pay on the due date while this is checked?”
   • “If I pay the undisputed amount now, how will you treat any remaining difference?”
     Get the answer in writing if possible.

7. If the wrong amount is collected, use the Direct Debit Guarantee quickly.
   If a Direct Debit is taken on the wrong day or for the wrong amount, contact your bank/building society and ask for a refund under the Direct Debit Guarantee. (A refund doesn’t automatically mean you don’t still owe the lender — it just fixes the collection error while you and the lender correct the account.)

8. If you can’t afford the new amount, ask for payment difficulty support before the due date.
   Use this wording: “I’m worried I can’t make this payment. What temporary arrangements can you offer so I don’t miss a payment?”
   Before agreeing, ask: “Will this add fees, change my term, or increase total interest — and can you confirm it in writing?”
   If you need independent guidance, you can also use free, impartial money guidance services.

9. Start a paper trail and escalate if needed.
   After the call, send a secure message in the lender portal summarising what was agreed. If it isn’t resolved, make a formal complaint to the lender. If you receive a final response you disagree with — or you don’t get a response within 8 weeks — you can take it to the Financial Ombudsman Service. If you get a final response, you usually have 6 months to refer the complaint.