House sold by FNB cracking!

FNB sold a new house to me and I am still paying bond for it. My house walls cracked badly 17 years later and I contacted FNB on the matter, as I am still paying for it. FNB refused to assist saying I should reported when I was buying it. My simple question is, how could I have known that FNB sold a house that would crack 17 years later? Some banks can be ****s, annoyed!