Massive bill call centre down

I received a bill for R3000 when my monthly average bill is around R750 to R1000. The invoice is vague and refers to data charges without any itemization or indication of dates. I have made multiple attempts to contact the call centre and have not yet been able to get in contact with anyone. Follow instruction to speak to consultant and call simply disconnects. Am at a loss how to query this bill when the customer care line simply does not work. If the bill can be explained and I must pay so be it but not being able to query a bill is unacceptable.