Mechanical Repairs: Genric Insurance

On 15 July 2015 I took out a mechanical warranty policy from Genric Insurance(AMW***) and this policy was reviewed again 17 March 2018 with a few alterations but the basic amount for all repairs and parts/components stayed the same. I had a few repairs done through the years and all were paid. On 4 July 2021 on my way to Upington the engine of the vehicle overheated and it broke down. The vehicle was towed to Kia Upington and on 17 May a quotation by Kia for the amount of R6424 was sent to Genric Insure. This amount was within the limit of repairs as allocated to me according to the Policies above. On the same day an approval was sent to Kia for repairs but only R 1500 was paid "for overheating" . Now overheating as I see it in any case is not repairs but a diagnose. I queried Genric and I was told that the Policy changed and it did not cover the claim for the engine repairs. I subsequently asked them on which date did the Policy change and why I was not informed of this new/change as in the past. . This is unacceptable and now they want me to bear the balance of the costs through no fault of mine. This I followed up on a few occasions via e mail but I do net get any feedback or a reply. Could you please assist me here