I’ve been thinking how to respond to you for a while now. My answer is a bit all over the place. Take it in bits and pieces if you need to.
First, take a deep breath. You’ve had a rough time with these folks and I think you’re emotionally invested in the outcome, whatever that may come to be.
I echo @dopamino - What is your plan for these logos? Again, you don’t have to say, but it’s good for you to have a clear idea of what you want to happen with them, and with you. Are you worried, since you deleted the source files, that you’ll have trouble with the company?
I don’t understand what is written in your contract. How are you supposed to give your employer the experience you gained when fulfilling your duties?
If you really want to know, you’re going to need a lawyer. If the lawyer says that the logos are your property and the company insists that the logos are theirs, are you prepared to go to court over this? Not only financially, but personally and perhaps professionally. It sounds like you are not parting on the best of terms. Is this a battle you really need to choose?
Honestly, this is the statement that worries me the most. I fear that you are seeing potential spite where none may exist and that you are approaching the situation with turbulent emotions, rather than cool headed thinking.
Oh, the stories I could tell about my last boss! I still struggle with bitterness. I worked for him on a social network that I still use, and the urge to rip him apart was strong for a long, long time.
Each time I start to brood about it, even after years have passed, I remind myself that my former boss probably doesn’t even spare me a passing thought. And that’s not a bad thing. It means that, when it comes time to ask him for a reference, he won’t have any negative emotions associated with me.
I know you only have a couple of days left, so finally, I’m on to my advice. In the years to come, you may look back on this decision with regret. Choices are like that. Which choice will you regret LESS in five or ten years? Choose that one.
I hope that wasn’t too convoluted to understand.
I have faith in you and I want the best for you. You will survive this. I just know it.