Spamming Twitter and Facebook using this hashtag in your own posts isn't going to contribute toward meeting the goal. Wait for the official postings and like/retweet them when they're available.
Here are the official posts to retweet: https://twitter.com/search?q=(%23pso2giveaway) (from%3Aplay_pso2) since%3A2020-09-16&src=typed_query&f=live
Facebook's not so clean because it is a dumpster fire, but these are the posts you're looking for:
https://www.facebook.com/search/top/?q=phantasy star online 2 - global %23pso2giveaway&epa=SEARCH_BOX