You need to contact a good lawyer in your area, hopefully one who practices in real estate. If you received a Notice of "Order Vacating Summary Final Judgment" as you describe, that is probably good news for you. In mortgage forclosures, the person who files or asks for Summary Judgment is normally the mortgage holder, or Bank. Your question suggests that the bank got the court to agree with them, and the court issued a "Final Judgment" which granted the bank's requests and agreed with their position. Later, something must have happened and someone - maybe at the bank, maybe in the court system - noticed a big mistake in your case. If the judge VACATED the final judgment, that means the judge UNDID it as if there was never a Final Judgment for the bank. "Dismissing Suit without Prejudice" means the entire lawsuit was thrown out - BUT the bank or Mortgage holder can file a new one if they want to and if the rules of court allow them. Your phone call to the lawyer for the other side tells you that you still "own the house" because the bank no longer owns the house because of the Order Vacating Summary Final Judgment. Guess who is going to get the tax bill at the end of the year? The owner. That is you. Get a lawyer right away to make sure all this is correct, and then you can move back into the house and try to figure out who will eventually contact you to try and get the balance of the mortgage paid to them, hopefully under a schedule of payments which you can afford, so you can avoid another foreclosure.
You should never have moved out of the house, and the Plaintiff's lawyer will have no idea what is going on.
You can move back in if you want to, but don't get the idea that they are just going to give up. It means some sort of strategy change is in the works. They may have sold the loan to one of the "vulture funds" that have cropped up, http://www.housingpredictor.com/hedgefunds.html
or to a debt buyer
You will be the last to know what they are up to, because in their world your interests are not considered. One thing you can be sure of is that they are not done with you.
I agree with the two answers already provided but will add that your mortgage sounds as if it is such a mess that a good defense on your part may hold off the foreclosure for a long time, perhaps years.
Learning from this experience, and if you choose to move back in, stay in and fight any future legal action. Pay the taxes but don't worry about the mortgage payment - who owns the loan and deserves payment? Your guess is as good as anyone's. And this is your defense, primarily - make the bank or plaintiff prove they own the debt.
Contact a foreclosure defense attorney who understands these issues and is willing to defend your case on the basis of standing, production of note and mortgage, and other defense strategies. After a review of your case they should have enough to protect you going forward.
Generally this is as if the suit was never filed. You should have a Foreclosure Lawyer review the order and let you know the timeline and what you can and cannot do.