Don't trust Telkom's 'Upgrade' to Wireless Service

I am a prepaid customer of Telkom. I was offered an upgrade to a wireless service with the assurance that nothing would change from my previous service, ie credit would be transferred and the voice mail service would stay the same. I now have a very nice cordless wifi phone but the credit wasn't transferred and there is no voice mail service. I discovered this after numerous calls to Telkom explaining my problem many times, being given instructions that didn't work, until an honest Telkom employee told me that I shouldn't have been told everything would stay the same, there is no voice mail service with the new phones. I use this particular phone for work and of course it's essential I have this service, as it would be for most people with a land line. I will have to discontinue my use of Telkom.