Well, it seems you are a collector and thus appearance dominate. Dead precise fit and precision is the realm of Modern knives - not that this can be used as a defence of shoddiness of construction in Traditional knives. I don't feel this IS shoddy construction though.
Since it seems to actually cause you anguish I would advise returning it for a refund even if you lose out (should be able to reclaim import tax from customs if the product is returning to the country of origin though) You'll never reconcile with the knife and you'll always be annoyed with it. As for selling it, since it's not a FOMA GEC then you'll take a loss so better get you money back now.
I think it's always wise to wait at least a week before giving feedback, initial impressions good or bad can be unreliable, the euphoria of getting an expensive new item can lead to being over generous- one reason why I tend to view effusive feedback with caution. But what of your experiences with other Traditional knives in your collection, have they disappointed you with regard to F&F ?
I'd agree with
Jolipapa
plenty of GECs could be returned due to their patchy performance as regards pin finish, complaints about F&F issues with CASE/Bose Collabs are not unheard of nor Customs either. Sometimes, people just anguish too much about the detail and miss out on enjoyment.
Thanks for your reply again, very helpful content, though I didn't understand some abbreviations, eg.g FOMA GEC, F&F (tried to search on internet, but get some different meanings), and "Monday Knife" as
kamagong
replied.
I wrote email to the manufacture, asked return and refund,
they replied that
my satisfaction is their commitment, they will replace the handle rather than make me unhappy. 
and they don't accept DHL or Fedex but just standard delivery, this means I need to wait over weeks / months and the parcel may got lost.
Replied again to ask what if I just wanted a return and refund instead of repair/replacement of handle, got a yes answer.
Ya, sometimes I concentrate in details a lot, this makes something good (to my work) and something not good (as in this case), as you said, I just focus in detail too much, miss out and forgot the rest great parts of the knife.
Why I post this topic, is wanted to see
if this is a common situation in Laguiole knife (high end, pricy, 238EUR level)? is acceptable? so that I can see if I will continue my further buyings of other traditional knives (other Laguiole, LE Thiers, etc.) online and through same brand and manufacture.
Now I know, seems this is not common but also not a big problem or defect, from the product point of view, not from how the manufacture's attitude to their products.
I did a lot studies before this time purchasing as my first Laguiole, Fontenille Pataud had some good reviews and posts, and because it's about 50-90EUR more expensive than Fordge De Laguiole, I though they will have much better quality control, that's why I choose FP. I may just had too much expectation to the quality control due to the expensive price.
Regarding on the rest of traditional knives in my collection, very "funny", I am the bad luck man.
In my collection, there were 7 traditional knives, 4 got defect, 3 got return & replacement experience.
- The 1st Grohmann: #1 with stag horn handle, ordered online through the manufacture's website, the first time I receive it, the tip is not well finished, I posted in this forum and apparently I was advised to replace it, then 2nd time I receive the replaced one, the stag handle is obviously not symmetric, left piece is 2 times thicker than right piece, I posted in this forum too and was told it can happen to stag horn handle, but I still decided to drive over hundreds KMs to the manufacture's physical shop and finally get a good one.
- The 2nd Grohmann: #4 with buffalo handle, purchased in shop, at beginning, I didn't noticed the handle obviously got hit by something (or not well finished), some pits on the buffalo horn handle, I sent it to the manufacture and got fixed (same country delivery, quick and not pricy):
Before | After
- The 3rd Grohmann: #2 with precious stone handle, I went to the city by flight over thousand KMs for it, it seemed to be a 2nd-hand knife, the blade is full of scratches on the surface, but I accepted it (because of the experience from 2nd one, I know in Canada, some shops sell used items, though I was told it's completely new). And I don't have time to wait in the country, I just went there for travel and buy that knife.
- The 4th Opinel: #8 Mushroom, same to the 2nd one, handle got hit by something, some pits, I sent them back and replaced it. (dealer is in same country, very fast delivery and no price paid as there is delivery insurance)
So this Laguiole is my 8th traditional knife and the 5th have "defect" (or imperfection). I do buy lottery every week, never have so good luck.
Though finally they said I can get refund, I think I might just keep this knife, just don't want to waste time and my mind. It's as a lesson to my knife collecting journey as well.
Having a good lesson is enough, with review of the past purchasing history, I think I can stop buying knife online if there is no "delivery insurance" and no "unconditional return & refund service" (though I have sound reason).
As bad luck man, I will stop buying knife for a while, next time if I wanted to buy, must physically check the goods carefully or choose online dealer in same country, have delivery insurance and unconditional return & refund policy.
I am not traumatized, though in the past days I think a lot (return or not), viewed a lot photos, plus I choose FP because of the expectation on the basis of "expensive price, better quality".
Reading your replies and by writing here, is the termination of the story of this knife.
Thank you Will Power, Thank you everyone viewed and replied this topic.