I received a default judgment against me from a magistrate court in Pennsylvania. I had answered the original complaint with an intent do defend but never received notice from the court regarding the date for trial. I called the court and the clerk told me they sent it regular mail, not certified, and they just assumed I got it.

I was told I had to appeal it with the Court of Common Pleas and pay filing fees, serve all other parties, etc.

How do I reopen this case?

... I was told I had to appeal it with the Court of Common Pleas and pay filing fees, serve all other parties, etc.

How do I reopen this case?

You want to re-open it or appeal it?

To find out how to appeal, I suggest you find the appellate rules (http://www.pacode.com/secure/data/210/partItoc.html)for the jurisdiction and do what those rules require.

But first, you might want to make sure the record contains evidence of the error you describe. Do this by filing a motion to reconsider with the trial court.