Repairs required on a newly built retirement house are unacceptable

My Dad purchased a newly built house from the Bateleur Estate in Nelspruit about four years ago. He has since passed away, but the cost of repairs exceeds R10 000.00 already. We have spoken to the estate maintenance department as well as the architects. Neither are prepared to instruct the builder to repair anything despite a 5 year latent defect clause between themselves. For example, the paint specified on the drawings has a 10 year guarantee. We now have to repaint as the water is ingressing into the walls causing internal cracks and warping window sills.