Ignoring my query

I phoned customer care to query a call I was charged for that I didn't make. I was told I would receive a response within four working days. It's now been three weeks (15 working days) with no reply. <br> <br> I have phoned customer care about six times only to be told each time by the call-centre agent that you will \receive a call from our technicians tomorrow."<br> I am still waiting for that call...<br> <br> I have sent them five emails in the 3 week period and each time I received an automated response that \""our technicians will contact you soonest.\"" <br> <br> They have no intention of settling the query and are hoping it will just die.<br> """