Payday loan

They have been calling me for the past two days demanding that I pay them $550 for a loan that I supposedly gotten and that if I didn't resolve the matter with them today the company they represent will be taking me to court and the guy told me to get a lawyer. I told him to send me validation of what I owe and who it's for and I would gladly make payments on it and they said they have several times that that no longer an option! SERIOUSLY!!