Debt Collector Notice

To make a long story short, I had a Target credit card, maxed it out, and was making the minimum monthly payment (which was getting me nowhere, but was at least making them). I moved out of state and took an extreme pay cut, and eventually stopped making any payments at all. For a couple of years I had gotten phone call after phone call, as did most members of my family. I ignored them all. I started receiving letters from a debt collection agency with an option to pay off the debt at a reduced figure. Stupidly, I threw them away, just hoping they would "forget" about me. This afternoon, I received a letter from the Law Offices of Howard Lee Schiff, P.C. stating that they are representing Midland Funding, LLC, who is the current owner (Target being the original creditor) and they "suggest" that I send them a check or a money order for the balance due, payable to them. Here's the thing: I do not dispute the validity of this debt. I know that I owe it. Do I reply to this letter? Do I ignore it? Do I call them to try to settle it for a lower amount or is it too late in the game for that now? It is very high ($8,102.89) and there is no way I can pay the entire thing off. They state to contact their office with any questions, not Midland Funding, LLC. I have been reading a million different websites on debt collection/DV letters/SOL/court appearances, etc... and am overwhelmed with contradicting advice. HELP!