Sub standard bank homeloans

I had paid R*** into my home loan in order to reduce my monthly payment of R18100 to R5800,Month end came and full amount of R18100 was deducted,I then contacted Standard bank and they asked me to send an email with all particulars which i did and was assured that the R12000 will be paid back,But yesterday when i checked my account the whole amount of R1150.000 was paid back into my account!I contacted Standard homeloans and the response was as usual,Sorry just pay it back to us.Now here is my problem. When i paid this money into my homeloan i had to get with my back Nedbank to up my daily limit which was a schlep as anything over a Million need special approval which took 1.5 days before i could transfer and not to mention the cost involved.I work out of country and only arriving back in SA late January which means i cannot transfer the money back to them.Which means it will be 2 x R18100 installments before i get home. My question is as follows,How was it possible that such a huge blunder was not spotted??I am sure that an amount of R1150.000 would have needed a series of signatures before being released and someone surely should have had questions about that amount! The level of incompetence in standard home loans is mind bogeling!!!