<human>: Can you summarize the given text in a few sentences?

I was recently mailed a letter from a collection agency that has switched the account number and the amount owed, so on the letter itself it looks like I owe an absurd amount (in the quadrillions). I'm wondering how to address this - do I just mail a debt verification letter asking the collections agency to verify the debt? What steps do I take after that? Can I use this in my favor with paying the debt off or disputing it? Considering this is an obvious fuck up on there part, but looks bad for me, I don't want to do anything that will hurt my credit score anymore than it has been affected already.

Some notes/backstory:

I had a CC about 10 years ago I maxed out on a Best Buy card, when I was a dumb 18 year old, buying an Xbox 360/games and a TV (about ~$1600). I wasn't able to keep up with it and it was charged off after all the interest kicked in (it was a "no interest for x months" deal with the card). 

I owe roughly $3700 currently, and it's been in collections for obviously a long time now. When I was first contacted about it via phone, roughly 5 years ago, I wasn't aware of my rights and the repercussions of my actions and admitted the debt to be mine, so statute of limitations in my state dictates the debt will not be wiped off my slate until sometime in 2018.
<bot>: collections switched the account number and debt owed on the letter they sent me and I now look like I owe quadrillions of dollars - what should my next steps be?