FNB Home Loans and Evaluators

We bought a property in 2018 in Mosselbaai Diaz Tweekuilen. In 2019 we asked our insurance (building) to have a look at a repair on the house as there was initially a problem with the geyser. Our insurance came back with a report from an engineer saying that the property roof does not have a certificate and that it was not build according to specs of NHBRC etc. They also informed me that the property that was rebuild does not have a occupation certificate. I called FNB home loans and asked them How the evaluator did not pick this up and how was the home loan aproved. Fnb informed me they need to resend the evaluator to get info on this. In the time I waited for FNB I also asked the engineer for the report from his side. He sent it to me and also informed me that the roof is busy pushing down and the property is currently unsafe I have asked for the report form FNB but to date its been 3 weeks and have not recieved any reply. I asked FNB to cancel the contract as this house was approved under false pretention and aslo is not the value of the property. Im not getting any feedback from FNB anymore and do not know what else to do to let them understand the urgency. Our lawyers also sent them a letter without any response!