Incorrect billing

I had a complaint anout incorrect billing last week. Today it's still unresolved, in fact it has gotten worse! Today a received a statement which states that I'm now liable for R13 000. How did we get there? Last communication from Vodacom was that I have a refund due and I owe 13k? I don't understand and I feel I'm being ******!

Can the operations/sales and finance teams get together and fix this problem. The poor service and inconvenience is just beyond pathetic at this moment!

So disappointing from Vodacom!