No Signal

I have never received a signal problem from Cell C when I was allowed to roam via vodacom, now I receive a message from cell C saying \ Cell C has upgraded its network in your area and you no longer need to roam on Vodacom. To experience the improvement please change your handsets settings to 'automatic' and restart your phone. For more assistance....."Well I never changed any settings and somehow automatically I can no longer roam on vodacom and can only roam on Cell C and I have no signal whatsoever as well as no access to the internet. This is the whole reason why I changed from contract to pre-paid. This is very frustrating and if not sorted out I will have to look for another mobile provider."""