Insurance claim

Good day I was involved in the smash and grab last year 9 of December ,I claimed my phone with Huawei care and Vivo cover which they told me I must pay access fee of 6300 which I explained to them that I would like to pay it in 3 months time they agreed approved claimed letter was sent to me .I stick to the agreement, I paid the amount in 3 months ,sent proof of payments when the payment was done Yesterday the 25 of March 2026 I received a message stating that their service provider informed them that the quotation for Huawei Pura 70 is no longer R15999, now it is R19 999 , which means there will be an additional excess which this was not discussed with me, i believe after I asked to pay the access fee in 3 months, they were supposed to ask their service provider if they will be an interest fee or price changed since I asked to pay the access fee in 3 months . I am really disappointed with their service. I asked for the refund which i'm not receiving any feedback about it