I've found my problem :D Messed up during the DNS setting. Placed it in the wrong connection (HAHA) Thanks again ! :)

I'll just list out what I did in steps so it'll be easier to find my (silly) mistakes.
First, I change the primary DNS of the 3ds done through the main menu to match the DNS of Pokecheck.
Then I go to the website and look for the pokemon I want to send over to the cartridge and click "Queue for Download" on the pokemon stats/info page at the bottom.
After that, I'll go to GTS with a full party and I should receive the pkmn but I don't. Am i missing any crucial steps ? Do I have to make any deposit requests (wanted and offered pkmn)

Thank you for your time :)

What do you want to know?

First of all, thanks again for answering my question earlier. Mind if I ask a few questions regarding Pokecheck, that's if you don't mind. I seem to be having a bit of trouble when reaching the GTS and making an offer part. Thanks :D