If you know that, even if you got the summary judgment motion re-opened and defeated it, you would still absolutely lose at trial, then there really isn't any point, other than delaying the inevitable.

For right now, if you want to go on fighting, you need to file a motion to vacate the judgment, because that procedural "error" deprived you of due process of law.  You would need to make clear that you have not ever received the other side's motion papers, so the court would understand why you aren't addressing whatever arguments might have been made against you.  It would still be a good idea to say why you think you can win this case.  If you can't afford to have a lawyer handle this, I'd recommend buying 30 minutes or an hour of a lawyer's time, a consultation, where you can get some more detailed help with your case.