What to do about finding the right debt collector?

I was checking my credit score online when I saw that my bill from charter communications when I lived in va was sent to a credit company. I called charter to get the phone number of the company the bill was sent to they gave me a different name. So I called the number they gave me. The company said they did not have that bill so I then called looked up the company I saw online and called them they said that they no longer had my bill. I have yet to receive a bill from charter or any of the credit companys since I moved I even did a change of address. I'm not sure what to do. I'm 24 I'm just starting to build my credit and this is ruining it. How to I find this bill so I can pay it.