Ruining my credit

In January of 2008, I recieved a bill from this company for a collect call that I recieved. I accidentally lost the bill, but didn't know what company it was or how to get ahold of them. They started calling me every hour until 9:00 at night when their offices close at 5:00, and I could never get ahold of anybody to talk to, it was always a recording even if you tried to call them back. Since the company is called QTBills.com I tried to look them up online to find that they have no website. Also since they were harassing me with phone calls that I couldn't even respond to, I Was a little suspicious of the company possibly being a scam or something. They finally contacted me and I told them that if they sent me another bill I would send them a money order. They informed me that they could not send me another bill and that I would have to pay over the phone with a credit card. I argued with them for about twenty minutes because by this time I really didn't trust them, and they finally agreed to send me another bill. I never recieved one, and maybe a month or two later I recieved another call asking for payment again. I told them about the previous situation and told them again that if they sent me a bill I would send them their money. Again they told me they couldn't, and couldn't give me a reason why not, and asked for my credit card information. I argued again until they told me a second time that they would send me a bill. I am still yet to recieve a bill, and now they have sent it to a collection agency. I was trying to ask the collection agency what I could do about this since I don't believe it should have been sent to them, since I told QTBills.com on more than one occasion to send me a bill and I would pay, and they agreed but never sent one. The collection agency however must be based in India as I could not understand any of their accents and I talked to more than one person. I don't believe they knew what I was saying and I had a very hard time hearing anything they were saying. I just want this whole thing straightened out. It's kind of funny, because the last thing the collection agency said is "we'll send you a bill". I guess we'll see.