home loan not approve by my bank of 15year while other banks approved it.

i was told that i do not qualify for a home loan with standard bank the bank i have used for almost 15 years without stopping while 3 other banks have approved it. after writing to them i was taken pillar to post. now i am sighing with Nedbank the which i do not have profile with. no body put an effort to check which i queried the calculation they used. i have a credit card, car loan, home home with you which i never defaulted by now this is how i am treated