However, when I used this account to link my steam account again, it showed that the steam account had been linked to another 2K account. I believe this is a strange bug between 2k and steam, because logging into the 2k website with my steam account showed "create your 2k account", so I created a 2k account with a new email address, and then logged into this new 2k account to find that the steam account was unlinked. Eventually, after struggling with customer service for days I managed to solve the problem.