Got a call from a process server saying to call Nationwide PreLitigation. They said I had a pending case against me.

Give no information over the phone. This could be a scam. If the process server is coming, so be it.

This description is strongly suspicious for scam. The first clue is the unusual behavior of the "process server." Payday loan extortion is rampant, perhaps due to the thriving industry of selling personal information harvested from loan applications by unscrupulous lenders which was the subject of an NPR feature this week. Prudent consumers would know better than to send money to someone they don't know to pay a debt they don't agree they owe. If they are really collecting a debt for something called Integrity Advance, you are entitled under the federal Fair Debt Collection Practices Act (FDCPA) to written documentation of the debt, which you should demand. Feel free to use the power of the internet to search names and phone numbers. Best wishes for a favorable outcome, and please remember to designate a best answer.

Yep, sounds like a scam. Let them serve you, but don't volunteer any information or go out of your way.

This is a common online payday loan scam. You should call your county's general sessions court and confirm that no suit has been filed against you.