OK, I mean zero disrespect in this post---but there's a lot that needs to be said here.
First, DO NOT TALK TO ANYONE ABOUT SETTLING ANYTHING. PERIOD. You have evidence in front of you that they filed a lawsuit against someone OTHER THAN YOU!! Why would anyone advise you to settle anything at this point? You said that the SSN they provided does not match yours---that's a stopping point right there. WHY would ANYONE try to settle an account when they just handed you potential evidence that they are barking up the wrong tree? This is a lot more common than you think--they skip trace to find possible matches based on same or similar names, and then go from there.
Second, the service is pure BS. You know it. We all know it. It's likely that someone did some skip tracing and found your facebook page, etc, and pieced together the description of you by looking at a photo. You said you were not at home that day. That's a second piece of evidence that they are barking up the wrong tree and playing games. If you look back at that proof of service document--the one with the physical description on it--there may be a date and time listed that they claim service occurred. One way to address this is to gather evidence that you were not physically located at that address at the date and time they claim you accepted the papers. Also, I would find out exactly who the process server was---their name must be on the proof of service. We can try to research them to see if they have had claims against them for fraudulent service before. The thing is this though--if you do nothing, they will file a motion for default--and they will get it. That means a judgment against you. Debt collectors do this nonsense quite often. If you can show that you were not even at home at the time they claim to have personally served you, you can also file a claim against the process server's bond for the fraud in many states. A lot of people blow this off, but I don't.
Next, DO NOT contact Cap 1 or their attorney at this point. You are very unfamiliar with this system--court, I mean--and talking to them know will likely lead to them tricking you into admitting something, etc. No good can come from you speaking with them right now. You said that they claimed a balance due of over $4K....and you mentioned having Cap 1 accounts in the past. Look back through your records, credit reports, etc--did you ever have a balance in that similar area as to what they claimed? If you did not, that's another red flag.
Look, do the best you can to try not to let this freak you out. Debt collector attorneys sue people every day, and more times than you know, they sue the wrong person. The SSN could just be all 9's on the paperwork, but it would seem to me that if they had to include an SSN, they would have at the very least taken care to put a legit one there.
So, let's try to simplify this a bit. First thing you can do is either go to the courthouse and file an answer, denying their claims that you owe them money. NEVER admit to the debt, especially when they may have tipped their hand already and provided an incorrect SSN. Or, you can write a letter to the judge explaining that you were NOT ever served, that you were not even home the day they claim that they handed you the papers. But the faulty service will most likely not be enough to get the case thrown out. The judge will know from your response that you are now aware of the lawsuit against you, which is the purpose of service. The judge will most likely just allow the case to proceed, since you're clearly aware of it now.
Another important thing you need to know before you do anything else---Cap 1 used to have mandatory arbitration clauses in their credit agreements. They do not anymore as best I can recall, but if this happens to be on an old account, there might still be an arb clause in effect, and if so, you need to know about it. You need to go to the courthouse anyway, so go to the clerk's office and obtain a copy of the summons and complaint, unless you already have gotten the whole thing online. The complaint often spells out some details, such as when the account was opened, when it went into default, etc. That info will help us to determine just how old this is, and what other options you may have. Get on this ASAP because you don't want them to file for default and get it in the meantime. If you post some of that info here we can help steer you in the right direction.
Also, know this---initially speaking with an attorney will not cost you money up front usually, but if you want to retain their services you will have to pay them up front there. Don't know if you have the budget to afford that or not. But any attorney worth hiring will want this same info right off the bat anyways, so you're not harming yourself by gathering it now. And yes, I would write that letter to the judge, explaining that you were never served, that you were not even at your home address on the day they claimed to have served you, and so on. You hopefully will be allowed some time in which to file an answer by the court--that would be the purpose of the letter, to buy you some time to properly research and respond.
