*****ing money

This company keeps sending threatening mails to pay a certain amount of money for what I have no idea. I was under the impression they assisted with loans but now I have some how entered into some or other agreement I am still not sure what it is and is now liable for this so called agreement. Could someone assist me as to what I should do as their next step of legal action is going to be a summons I would like to avoid this if I can?