I have a Human Resources background (state of Washington), and I can confirm, there’s good information here. Just to clarify, though: If you resign with two weeks notice, and the company elects to pay you the two weeks and make that your last day, that isn’t the same as firing you (technically called a “discharge”). You’re still considered to have resigned.
eulalia, your story reminds me of a piece of advice I can offer to everyone who’s looking at a job change.
Right before you give notice, ask to see your personnel file. In the vast majority of U.S. states (I don’t remember the exceptions, and I have no idea about other countries), you are legally entitled to look at your personnel file any time you want. You probably won’t be allowed to take it out of the department, but you can go to HR/Personnel and ask to read through it. (Remember to ask about secondary files, such as those maintained by managers, as well.)
As you read the file, make sure there isn’t anything weird in it, or that there’s nothing missing that you think should be in it, like a positive evaluation. You can ask to have the file amended, or, at the very least, you can give them a document to add to your file, something like “I disagreed with the facts of that one warning” or whatever if you haven’t done it already.
Then get a copy. Most companies have a procedure for this, and may charge you like a dime a page for the copy. The drawback of this is that you’re tipping your hand; HR will know that you’re probably planning to quit, or maybe that you’re acting on the advice of a lawyer. (BTW, IANAL. YMMV.) That’s why you don’t want to do this until right before you give notice. But you also don’t want to do this after you give notice, especially if you don’t trust the company to represent your employment history honestly. Deliberate deceptions are very, very rare, despite rampant employee paranoia, but it doesn’t hurt to cover your bases. (Most of the time, when stories differ, it’s simply because the HR department is behind on its filing, and there are additional bits of paper floating around. Make sure to ask about this when you get your copy.)
Anyway, if you get falsely accused of something, like what happened to eulalia, you have point-in-time documentation by which you can prove that the accusation is false and amounts to harassment and libel. In eulalia’s case, I would have called the head of HR at my old company, and explained what was going on. I then would have made this request: “Here’s what you’re going to do. You’re going to put something in writing. Either you’re going to put that accusation of attendance problems in writing, or you’re going to put a retraction in writing. Either way I expect a letter within five days.” And then hang up. If they put the accusation in writing, it’s lawsuit city, because you have the copy of your personnel file that demonstrates their accusation holds no water. And if you have the retraction in writing, obviously, they can’t make that accusation any more.
Just a few hopefully useful words of advice from someone who spent many years in HR.