So, with the new update we are supposed to be able to have up to 18 characters right? So, I had 1 ticket saved up, went ahead and used it to create a Glaivier, but I also wanted to create 3 more characters so I went to the store to buy more tickets, but it says I have reached the limit, meaning I have bought 12 tickets before, which I have not, I have only bought 7.
My main is Almadarius on Azena, US East
Hi @Almadarius
Welcome to the Lost Ark Forum!
I’m very sorry for the issue you are having with the character slot extension.
Please try to check the integrity of the games files and once you finish to do it try to buy again the ticket to verify if the issue still.
If the issue persist please contact our live support channel in order to verify if you have reached this limit and also to create a ticket to the devs team and they can investigate further what is causing this and help you with it.
Here is the link to contact live support channel:
Hope this information help you! 
I also have this same problem. I verified the game files, it did not work, submitting a support ticket now…