Deposit and bond grant

I app**** for a homeloan with Sa homeloans. They rep**** back to me that there is R990 against my name for a medical hospital. I did not know that my Medical Aid that is Discovery didn't pay that amount and was never contacted to let me know of any outstanding amount. As soon as i heard this i payd it in full to be removed from credit beurro.The Consultant at Sa Homeloans told me due to this, my Deposit wil now be 240 000 as they only grant 80%. How can this be over R990. Is this how they help people as highly advertised on their billboards? We only have R 100 000 deposit. We don't have R 240 000. Please help us to buy our dream home