Plz help me!
I'm sorry to say, but your DSi XL will not connect to the Internet under any circumstances because Nintendo shut down internet capabilities for those systems. So the only way you can get your Meloetta (which I assume you want On Black/White/Black2/White2) is through the use of an action replay/other hacking devices or from a trade with a friend/relative who could possibly have one.
Source: Knowledge
'm sorry to say, but your DSi XL will not connect to the Internet under any circumstances because Nintendo shut down internet capabilities for those systems.
That is true but if you can figure it out, I'm pretty sure you can use a private server or fake GTS. If you know a friend who has one you can still use infrared to trade.
Source: Experience