Dissapointed with NMI South Africa

I purchased a Mercedes Benz CLA 45 AMG from Natal Motor Industries (NMI) in Umhlanga Durban in 2015. On the 25th of July 2016 the said vehicle was flooded during inclement weather in Westville Durban. A claim was registered with the insurer (Santam) who then conveyed the vehicle to TechnoStar Autobody Repair Center. the repairs were authorised by Santam and was duly completed on or about the 13th of September 2016. An inspection was completed by NMI on completion of the repair and was found to be satisfactory. On the 25th July 2017 it was noted that the vehicle began smoking from the region of the engine bay whist being driven. the matter was immediately reported to NMI who then carried out their initial diagnosis. Their diagnostic report indicated that there was a hole that had broken through the cylinder block as a result of the water ingress when then vehicle was initially flooded. The vehicle was then inspected by JPA Mechanical Appraisals cc. on the instruction of Santam, who concluded that the only reason for the engine failure was due to a part failure i.e a connecting rod in the engine and not as a result of water ingress. The insurer (Santam) has since denied any liability based on the findings of JPA Mechanical Appraisals and NMI is denying liability based on their findings which stipulates that the engine failure is due to water ingress. it should be noted that the report completed by JPA Mechanical Appraisals was more comprehensive than the report completed by NMI. The vehicle is still under warranty and has been parked at NMI premises since the 25th of July 2016. All monthly instalments and insurance premiums are currently up to date with no defaults. This matter has been handed over to my attorneys and the matter has been submitted for arbitration, however attorneys acting on behalf of NMI have been unreasonably delaying the arbitration process and have not yet agreed upon a date for the arbitration to proceed. In the interim I have received a quotation from NMI for repairs that need to be conducted in the amount of R627 433.30. Taking into consideration all of the above mentioned details, it can be clearly noted that there was no negligence on my behalf and I should not be held liable for any payments regarding this repair. I seek your assistance in resolving this matter amicably.