Billing Dispute

I logged a dispute in August and then again in October that I did not receive feedback on. No-one can tell me what is going and how long it will take to resolve the dispute. Initially it will take up to 3 weeks, then 4 week, then 5 weeks. I am going for 6 weeks now. No-one will put me through to a supervisor so how do I escalate this? When I spoke to Ester she said she will escalte this but it does not help.