Dorsey thorn and associates

I have been contacted by this company for little while now. I told them that i wanted them to send me some information showing the amount that i was told i owe.They would not send me anything at first i received a email from them a few months ago stating i owe over 700 dollars and i didn't hear from them again for 3 months then they called me today and left me a message. I told them that i would pay if i got the information i need but this company does not seem like they are very professional. I was hoping someone can give me some information on what i can do.