insure by iStore *******

My phone is insured for R20 899, I submitted a claim and they approved it for a R14 000 phone. They are refusing to give me a R20 899 worth of phone. Saying they have a right to pick a phone for me, I don't have a problem with that but it must be worth the amount insured for Their complaints department is horrible they take time to respond to complaints and won't give full explanation. I took the matter to the ombudsman