Home insurance claim rejected

I have purchased my home 3 years ago, I have a bond with standard bank, before my bond was approved an assessment was done on the house by standard bank and approved. <br> <br> I recently notice my walls of the house cracking and reported to standard bank, the sent a loss assessor to the house, he then requested for an engineer to have a look At the house. He came in and took a few pictures and said he will submit his report and standard bank will be in contact with us, 3 weeks had passed Without any news, when we called in the lady said claim rejected, due to defective construction and active soil, we asked for a detailed report to be given as to why rejected we have not heard from them , my question is why insure my house in the 1st place if you sent people from standard bank the asses my house before bond approval and now say defective workmanship could that have not been picked up in the 1st place also after reviewing my policy it clearly states we covered for subsidence damage. I need to know why my claim is rejected, this is unfair, I have been paying premium s for 3years. I've called in 2 engineers and they said the Can't understand y the bank rejected claim. Very sad