summons

I have a question. I received a summons and am responding to it as per the advice on your website. My question is: Mine has the original credit card co. that I owe as the plaintiff but the summons is from an attorney and at the bottom it says in small print this communication is from a debt collector and is an attempt to collect a debt.... so is this summons from a junk debt collector or is it from us bank cause they are named as the plaintiff... I also have no court file no. so who do I send it to at the court... it just says district court, second judicial district but no file no. thanks in advance of responses.