decline of home loan application

i am nedbank customer for more than 7 yrs , i am very angry with them and dissappointed , i app**** for home loan finance was declined they want me to pay 20% where must i get the deposit because they know better than me , FNB approved my application but my own bank decline it , i am going to move all my accounts with them and i would never advice anyone to bank with them , IM VERY ANGRY and i dont why my company banked with them they are useless , i have credit card with them,investment, current and 3 children had accounts with them but at the end of the day they cant even assist me .