No help with resolving claim despute

I submitted a claim for repairs to my motor vehicle. Discovery authorised the claim and the repairs went ahead. This included replacing parts on the vehicle. A few weeks after getting my car back from the panel beaters, I discovered that the parts weren't replaced, but merely repaired. Parts of the bumper was also assembled using cable ties. I have quotes and assessments showing that the parts were to be replaced. The bumper now keeps pulling loose due to the shoddy workmanship. I have contacted Discovery on numerous occasions to rectify the matter, with no response.