Hello,
You are normally supposed to receive a warning message when a Pokemon from another region is being traded to you, did you notice it ?
I looked at your Trade History and found a trade between you and Mateus000 including a Dragonair you bought 55k.
If that trade was indeed a regular buy, we can not intervene or transfer the pokemon back to the other player as if it was for an "evolution" trade since money is involved here, you can still try to talk to the seller and possibly try to convince him to reverse the trade then posting the proof here.
Otherwise you'll have to wait written region to be able to play with that Pokemon. Try to be careful with it in the future.