I'm surprised Olfa won't replace your obviously defective mat. Perhaps you should write a letter or email to the company president and include the pic of your mat. I'd also include who you talked to and what they said. It would be different if the mat was old, but for it to start peeling like that after only four weeks signifies (to me, at least) that it's defective. I'll bet if you go straight to the top you'll get a more satisfactory response.
Edit: I posted this before I saw your last post. I still think you should go straight to the company president. It's worth a try, at least.