LVNV/Resurgent Capital Svcs/Creditors Interchange

Hi - Yesterday I received my first notice from the above CA...with 3 different names? Anyway, I was short on a pay-off ($200 keying error, my fault), never rcvd a phone call from the cc company... but, that's my fault, I thought about it several times on how I didn't get a notice saying the account was PIF. Never did anything about it. Now this place is saying that I owe $850 and that charges are accruing daily and if I dispute, I'll have to pay the balance, which by then would be closer to $1000! (This is what the rep told me.) He also said that if I dispute, that they will not work with me on a settlement. I am not trying to get out of paying, but $850 for a $200 bill? That just seems like a ton of interest and fees (over the span of 8 months). Any advice I can get would be much appreciated as I've never dealt with CA before. I'd happily pay the $200, I'd even settle for $300 just to get this resolved. Thank you!