No response after month and a half

I received a bill of almost 3 times my average spend in July and queried it on 4 August in store. No one came back to me so I phoned and logged another query on 4 September. I still haven't heard anything and phone again today just to hear that apparently the query (ref ***) was logged incorrectly and they had to log a new query (***).<br> <br> I had to pay the invoice and now that I query it no one can assist me. I was away for a week during which I didn't use any data but still I was billed 3 times my normal usage. It is unacceptable to wait more than a month for a query to be resolved. They even told me I must phone again to follow up if I don't hear anything back in 3 days. <br> <br> Worst service ever....