Failure to assist with riaming issue when abroad

My moms phone was set on roaming prior to departing uk for her holiday in SA with me. Her phone is not receiving anything no sms no calls. Have contacted Virgin Media by all forms of communication available including my sister in the uk calling. Its been nearly a month and her phone still not active. A big ckmpany like this should have sorted the problem out immediately not just leave it unresolved!!!!! Upon her return she will be looking for a new provider cause clearly Virgin Media customer service / care is not part of the service