Vodacom
Not committing to insured band

I have a blackberry z10 which was damaged beyond repair. It is insured with Vodasure in band 5 and I have been consistently paying this premium. When its time to replace the phone now I get informed that if want a phone similar to the one insured I will have to pay a co-payment of more than R4000 despite the fact that the requested phone (the blackberry z30 falls well within my insured band). The insurance policy clearly states that the maximum amount payable in the event of a claim shall be determined in accordance with the prescribed premium bands at the time of inception of the contract.