Invoice Issue

This is my second complaint and still, no one has called me, this is really sad. This time, I am inquiring about an invoice that I received in Jan which I called in and inquired about. I was informed that someone from accounts would get back to me but nothing till today. I then called again last month, and now the person I spoke to said he could not view any notes on his side about my last call query. I am sitting with a case now that I still have not received an invoice since I have joined and no one is calling me about the case I opened in JAN