Continental Finance ,First Bank Of Delaware, "collections/billing department" harassing phone calls Newark , Delaware

A few years ago, I got this card in the mail. It was one of my first credit cards ever.  I had a limit of 500.00 I charged 50.00 to it and paid it off and called four times for them to close my account. I hear nothing from them or get any more bills for a few years.  Then about a month ago, I get a phone call from their "Collections Department." They proceed to tell me that I owe 978.34 which is the limit plus intrerest. I explain to them that I have no money at all. She then tells me that I should get someone to loan me the money and call her back when I get their credit/debit card numbers.  I tell her that's not possible. So she then tells me that they are going to send a process server to serve me with papers. I tell her to go ahead and do what she has to do. I hang up. 

Two weeks later I get a call from them again. Different person this time, they say that there were two failed attempts to serve me with papers from the county clerks office and if they don't hear from me within the next 24 hours they will assume that the third attempt was a success and I will show up with my lawyer on the date subjected on the papers.  So I call them back and basically call them liars because I had been home for 4 weeks and no one had even tried to show up with papers. So then she continues to tell me that if I just give her 50.00 with a credit or debit card number that would stop the process servers. I asked if she would accept a check or money order, she told me no.  I told her I would see what I could do. I then called the county clerks office here in my town, and was told by them that they don't do the process serving, that is the Sheriffs Departments job.  She looked my name up anyways and said that there was nothing filed against me. Then to tell the people that were harassing me that I have notified the local police department.  I then called the "collection/billing" lady back (who also informed me that she was a paralegal at the law office of the attorney who was going to take me to court but every time I called they answered the phone saying "Billing Department") told her that I wasn't giving her anything, and that I took it upon myself to call the county clerks office and was told that nothing was against me, and that I notified the police. She then got all defensive and told me that the reason nothing was showing up was because they hadn't filed it yet, and she hung up. 

Riddle me this...if they hadn't filed yet then why were they saying that there was two failed attempts to serve me with papers?? I strongly feel that this place is a scam.  Also, I was told that if a credit card company is going to take me to court they will send me a warning letter. I never got one of those.