it takes a long time and occasionally you need to be proactive about making it happen. Here's what should happen:
after the contest finishes, which could be another 2 weeks beyond when the site shows the actual winners, you'll be contacted by the sponsors representative. they'll take your info and it'll get sent out within a week or so from there. international shipping times vary greatly. it's probably coming with the cheapest post paid.
And of april for a feb contest wouldn't be unusual, but you'd be contacted long before that. it once took 6 months for a sponsor to send my seeds out and chose not to send the swag bag, so i got 2 extra seeds, lol.. gee thanks.. this stuff is quite informal, unfortunately.
if you arent contacted within a month of you pop up window indicating you won a context, start DM'ing gd and the sponsor's official profile if they have one.. if not contact them directly on their website with a proper and courteous explanation.
keep up on it from there, but don't be scrappy-doo.. cross paths with the wrong malcontent and tehy will 'tax' you for expecting what was promised, lol, and somehow it'll be "your" fault. humans are just waiting for an opportunity to act offended over nothing for the last decade or so.