Blindsided by 14 yr old debt claim

Hoping you guys can help me here. I got a call this morning on my cell phone from a woman claiming to be with PRA. Told me I owed over $800 on a debt with Verizon and asked if I could make the payment all at once or needed a payment plan. Since I had *no* idea what she was talking about, I started asking questions. When she told me that this was dating back to 1996, I attempted to stop the discussion immediately by asking for details in writing, that I was not going to simply hand over hundreds of dollars to someone who just called my cell asking for it. She told me that the letter had been computer generated, and that it was impossible to send a new letter. Bull***t. She then told me that they had been trying to call me but kept on getting voicemail - I've never heard from these people. Told me that she'd called my brother (???) in 2008, but he said he didn't have my number. (He's never mentioned this.) And they didn't have his number because he'd asked that it be deleted. She then said that they'd sent everything in writing in February because they hadn't been able to get me via phone. I was confused - she'd just said a letter had been sent a month ago, but now it's February? She apologize and said she'd made a mistake. At this point, I asked for a supervisor.

Supervisor told me that a settlement offer had been mailed to me (in my maiden name) back on February 2nd, and that it expired on March 19th. She said it was with Verizon, and that PRA acquired this debt in 2004. (So why no call til now????) Told her (possible mistake here) that I had no idea what the debt was from, that I'd had a Verizon account back then but KNOW I would not have let anything like that go unpaid, and that I needed written verification. Also told me she couldn't send anything in writing, but I pushed back and said I would not pay anything until I, and my attorney, got something in writing to review. Asked what the amount was again - she said $335.27, but then said that this was the settlement offer and that she couldn't send anything written without an agreement to pay. Told her again I would not pay anything without further written details, and asked her to fax the information this afternoon. Also told her that if my attorney and I reviewed it and found it to be valid, that I would of course honor any debt that was truly mine.

Asked one last thing - told her I'd pulled my credit last year for a mortgage re-fi, and had just been preapproved for a mortgage (again, possibly big mistake). My credit is in the high 700s, I have no debt, why am I not seeing this on my report? She told me that because it's beyond 7 years so it won't show up here. But here's the kicker:

She then said, "You're lucky that we haven't pulled your credit yet. Once someone does, and any rep has the ability to use their own judgement and pull it at any time, they can post this issue to your credit." She said that it hadn't happened yet because they can't do anything to my credit until they make contact with me. Now that they have, they can. This got me heated - I told her that if this had (supposedly) been going on for so long, why it's just now that they've contacted me, and that what she had just told me sounded very threatening. She was very quick to say she wasn't threatening me, but I pushed back, albeit civilly, and told her that her response was very unfair and did come across as very threatening as they were asking me to pay something I had no written verification of.

I ended the call by promising to go home and turn my fax on so that she could send details in writing. I did so an hour before my promised time, could not get the original supervisor on the phone, but asked the rep at that time to fax a debt validation. She said she would within 24 hours.

So... and I know this is super long... what are my options???? This seems way past the statue of limitations (was in IL at the time of this debt, if it's mine), but I'm worried. I did have a Verizon account, but do honestly believe that I paid it off in full but have no paperwork to back it up. If it's mine, I'd pay it, honestly... I'm capable and willing, but only IF IT'S MINE. We really are preapproved for a mortgage at a great rate and will hopefully be moving by the end of the summer - it would kill me if this got in the way. If I pay it, can I be assured that it's really done? Part of me just wants to pay to not have to worry about the credit. For me, my credit score is invaluable... is it better to just pay the $335 and be done with it?

Any advice would be greatly appreciated. Thanks!!