Creases in new thin-mousepad chess board...

edit: TL;DR - I have bad memories of creased vinyl mats in high school and was excited to get a new thin mousepad board.  It came folded and after several attempts to flatten, still terrible creases.  Suggestions?

original post:

Hi all.  Like many people I was super basic and recently started to get back into chess after many years - haven't really played since high school.  It was a big deal in high school for us, extending well past club, oftentimes getting chess sets confiscated due to poorly timed/unruly behavior.  One classmate recently reminisced that our teachers likely would have preferred actual wrestling matches... sorry, bit off topic.

But it sets the stage for my long-standing frustration and annoyance with vinyl mats. We all used them due to obvious portability but constantly fighting the curl was annoying.  So when I started looking at new/modern club style sets a few months ago I saw the newer thin mousepad style and I was so excited.  That's exactly what I wanted, and I've experience with the material as game mats from Warhammer.  No need to worry about wrinkles and rolls.  Excellent!

I finally placed an order with an independent shop through eBay for one of the new Ultimate Chess Pieces sets bundled with one of the ACE woodgrain mats.  

Of course it arrived folded, in the box, no worries, because no wrinkles, right?

Wrong.... it's been two weeks of trying to get the wrinkles and creases out.  So far i've tried:

• Two days under about 60 pounds of heavy hardback edition graphic novels. This had no effect
• Ironing.  No effect.
• One week under an old MDF chessboard with 300 lbs of weight plates on it.  This appeared to have some effect... but over the course of the last few days all the wrinkles and creases that appeared to have decreased only came back. 

I'd post pics but it seems like maybe new accounts aren't able to? 

Anyway, I'm just confused and kinda frustrated.  My understanding was this wasn't really a thing with thin mousepad boards.  I'm the obsessive type who reads way too many reviews before making a new purchase, I even read through a discussion where there was some argument about how this COULD be a thing after long storage folded, but no one had actually seemed to experience it happening.  

But yeah, would really like to get this flattened, but after the last experiment with the weight plates I'm starting to think I'm just gonna have to leave it unused under weight for ... months?  a year?  Its usable but not the experience I was looking for  Every one I see on line in videos or photos are just so perfectly flat.  So... ideas?

Yeah it may come to that.  The seller had a note, standard on their packing slip it seems, that folded mats will lose crease "after time."  Starting to think however they stored it while waiting for it to sell has resulted in permanent creases.  

I put a photo up on a common image sharing site but apparently the board's automoderation code recognizes just mentioning the site as attempting to link to it and shuts the post down.... 

yeah, i rather expected they would be shipped similarly to the way my warhammer mats are shipped.  Those are 6 feet by 4 feet!. They are usually rolled, then sort of curled up in the roll to fit a standard shipping box - makes no tight folds so no creases...  *shrug*