Unable to make contact and Insure my phone

It is very frustrating calling the C Surance (Cell C Insurance) and having the call fail everytime. I upgraded my cellphone contract on the 06/04/2015 and wanted to insure the new device but i was advised that i needed to call the number provided, ***. I got through the first time i tried but they then advised me that i first need to cancel the insurance on my current device as it is the same number but i was never able to get through to the call centre again. I desperately want my device to be insured before anything happens to it