You have to buy the game. It's still has broken issues that will never be fixed because Maxis is gone.
Only way they will transfer a game between accounts is if you own both accounts and they will merge the accounts together. A family member had two because he forgot he owned one then bought Dragon Age Inquisition and EA support got his two accounts combined. He had a struggle doing that but they will not do that if the accounts are in different names.
I would suggest buying Cities Skylines over this abandoned game at this point. At least Skylines still has devs working on it. Steam had it on sale just this past weekend.
