An application runs through two separate tests, and it is worth knowing which one you are failing. The first is your credit record: your payment profile with existing accounts, any defaults or judgments, and how many credit enquiries you have generated recently. Bureaus in South Africa score on their own scales - several run from roughly 0 to 999 - so there is no single national cut-off, and the number your bank sees may differ from the one your insurer sees. The second test is affordability, and it is the one written into the Act: your gross income, less statutory deductions, less a prescribed minimum for living expenses, less every existing debit order, has to leave enough for the new instalment.
Why identical scores get different answers
Two people with the same score can walk away with completely different outcomes because affordability is arithmetic about this month, not history about last year. If R14 000 lands in your account and R11 500 is already committed to rent, transport, groceries and existing repayments, an instalment of R1 800 does not fit no matter how good your intentions are. Lenders will either decline it or offer you a smaller amount over a longer term. This is also why the amount you ask for is a lever you control: requesting R15 000 instead of R40 000 changes the instalment, and with it the answer.
Read your own record before a lender does
You are entitled to one free credit report a year from each registered credit bureau, and it is the cheapest hour you will spend on this. Errors are common - accounts you settled still showing as open, a default listed twice, an account that was never yours. Bureaus must investigate a dispute you raise and correct anything they cannot verify. Fixing one wrongly listed default can move you into a better rate band, and it costs nothing but the email.