Depleted data? "Customer Care"? Really Vodacom?

Logged a call at Vodacom "Customer Care" regarding my 80 year old mother who has not been able to make outgoing calls for the last 24 hours. Apparently this is due to the fact that her data was depleted on the on the 15th of this month, and that her balance was R0 on a top up contract. Vodacom... Please explain to me how this is at all possible when 1) I have a call log on my phone of calls received from her up until 20 August, and 2) She NEVER uses her mobile data as she is situated permanently in a home with WiFi?? Evidently you are able to log an enquiry - but be warned this takes up to 7 working days. Customer Care - REALLY???