How do I verify my Wi-Fi with Nintendo for my DSi? Read detail!?

My Wi-Fi works on the internet browser on my DSi, but when I try to get on it on Grand Theft Auto: China town Wars through your computer in the safe house it says I don't have any even though I set it up with the correct password and it even had 3 full bars, but when I test the connection after I set it up it doesn't work. The person on my last question told me to verify it with Nintendo, but I thought I did something like that already where I had to call them and the internet service, but it still doesn't work with syncing my stats on GTA for the Rockstar Social Club. Please help!